diff --git a/classes/courseinfo.php b/classes/courseinfo.php
index f77aea7..d27a15b 100644
--- a/classes/courseinfo.php
+++ b/classes/courseinfo.php
@@ -34,6 +34,7 @@ use \grade_scale;
 use \grade_outcome;
 
 class courseinfo {
+    /** @var string */
     const TABLE = 'course';
 
     private $course;
diff --git a/classes/courseservice.php b/classes/courseservice.php
index 2e25357..62d50ba 100644
--- a/classes/courseservice.php
+++ b/classes/courseservice.php
@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <https://www.gnu.org/licenses/>.
 /**
- *
+ * Webservice related to courses
  * @package    local_treestudyplan
  * @copyright  2023 P.M. Kuipers
  * @license    https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
@@ -30,27 +30,48 @@ use \local_treestudyplan\associationservice;
 use \local_treestudyplan\local\helpers\webservicehelper;
 use \local_treestudyplan\completionscanner;
 use \local_treestudyplan\gradingscanner;
+use \core_course_category;
 
+/**
+ * Webservice related to courses
+ */
 class courseservice extends \external_api {
+    /**
+     * Capability required to edit study plans
+     * @var string
+     */
     const CAP_EDIT = "local/treestudyplan:editstudyplan";
+    /**
+     * Capability required to view studyplans (for other users)
+     * @var string
+     */
     const CAP_VIEW = "local/treestudyplan:viewuserreports";
 
-    /************************
-     *                      *
-     * list_courses         *
-     *                      *
-     ************************/
 
+    /**
+     * Return value description for map_categories function
+     * @return \external_description
+     */
     public static function map_categories_parameters() {
         return new \external_function_parameters( [
             "root_id" => new \external_value(PARAM_INT, 'root category to use as base', VALUE_DEFAULT),
          ] );
     }
 
+    /**
+     * Parameter description for map_categories function
+     * @return \external_description
+     */
     public static function map_categories_returns() {
         return new \external_multiple_structure(static::map_category_structure(false));
     }
 
+    /**
+     * Structure description for category map, used in a number of return descriptions
+     * @param bool $lazy
+     * @param int $value
+     * @return \external_description
+     */
     protected static function map_category_structure($lazy = false, $value = VALUE_REQUIRED) {
         $s = [
             "id" => new \external_value(PARAM_INT, 'course category id'),
@@ -68,6 +89,12 @@ class courseservice extends \external_api {
         return  new \external_single_structure($s, "CourseCat info", $value);
     }
 
+    /**
+     * Get a category map, and optionally specify a root category to search for
+     * User's top category will be used if none specified
+     * @param int $rootid Optional starting category for the map
+     * @return array
+     */
     public static function map_categories($rootid = 0) {
         global $CFG, $DB;
 
@@ -97,22 +124,41 @@ class courseservice extends \external_api {
         return $list;
     }
 
+    /**
+     * Return value description for get_category function
+     * @return \external_description
+     */
     public static function get_category_parameters() {
         return new \external_function_parameters( [
             "id" => new \external_value(PARAM_INT, 'id of category'),
         ] );
     }
 
+    /**
+     * Parameter description for get_category function
+     * @return \external_description
+     */
     public static function get_category_returns() {
         return static::map_category_structure(false);
     }
 
+    /**
+     * Get category info by id
+     * @param mixed $id
+     * @return array
+     */
     public static function get_category($id) {
         $cat = \core_course_category::get($id);
         return static::map_category($cat);
     }
 
-    protected static function map_category(\core_course_category $cat, $lazy = false) {
+    /**
+     * Create a category map, given a specific category
+     * @param core_course_category $cat The category to scan
+     * @param bool $lazy If lazy loading, do not scan child categories
+     * @return array
+     */
+    protected static function map_category(core_course_category $cat, $lazy = false) {
         global $DB;
         $catcontext = $cat->get_context();
         $ctxinfo = new contextinfo($catcontext);
@@ -142,16 +188,29 @@ class courseservice extends \external_api {
         return $model;
     }
 
+    /**
+     * Return value description for list_accessible_categories function
+     * @return \external_description
+     */
     public static function list_accessible_categories_parameters() {
         return new \external_function_parameters( [
             "operation" => new \external_value(PARAM_TEXT, 'type of operation ["view"|"edit"]', VALUE_DEFAULT), ]
         );
     }
 
+    /**
+     * Parameter description for list_accessible_categories function
+     * @return \external_description
+     */
     public static function list_accessible_categories_returns() {
         return new \external_multiple_structure(static::map_category_structure(true));
     }
 
+    /**
+     * [Description for list_accessible_categories]
+     * @param string $operation
+     * @return array
+     */
     public static function list_accessible_categories($operation = "edit") {
         if ($operation == "edit") {
             $capability = self::CAP_EDIT;
@@ -170,7 +229,13 @@ class courseservice extends \external_api {
 
     }
 
-    public static function categories_by_capability($capability, \core_course_category $parent = null) {
+    /**
+     * [Description for categories_by_capability]
+     * @param mixed $capability
+     * @param core_course_category|null $parent
+     * @return array
+     */
+    public static function categories_by_capability($capability, core_course_category $parent = null) {
         // List the categories in which the user has a specific capability.
         $list = [];
         // Initialize parent if needed.
@@ -199,7 +264,12 @@ class courseservice extends \external_api {
         return $list;
     }
 
-    protected static function recursive_child_categories(\core_course_category $parent) {
+    /**
+     * Recursively create a list of all categories unter a specified parent
+     * @param core_course_category $parent
+     * @return core_course_category[]
+     */
+    protected static function recursive_child_categories(core_course_category $parent) {
         $list = [];
         $children = $parent->get_children();
         foreach ($children as $child) {
@@ -211,16 +281,29 @@ class courseservice extends \external_api {
         return $list;
     }
 
+    /**
+     * Return value description for list_used_categories function
+     * @return \external_description
+     */
     public static function list_used_categories_parameters() {
         return new \external_function_parameters( [
             "operation" => new \external_value(PARAM_TEXT, 'type of operation ["view"|"edit"]', VALUE_DEFAULT),
         ]);
     }
 
+    /**
+     * Parameter description for list_used_categories function
+     * @return \external_description
+     */
     public static function list_used_categories_returns() {
         return new \external_multiple_structure(static::map_category_structure(true));
     }
 
+    /**
+     * List all categories available to the current user for editing or viewing studyplans
+     * @param string $operation The operation to scan usage for [edit, view]
+     * @return array
+     */
     public static function list_used_categories($operation = 'edit') {
         global $DB;
         if ($operation == "edit") {
@@ -255,6 +338,12 @@ class courseservice extends \external_api {
         return $list;
     }
 
+    /**
+     * List all categories available to the current user for editing or viewing studyplans and add information about their usage
+     * (Not a webservice function)
+     * @param string $operation
+     * @return stdClass[]
+     */
     public static function list_accessible_categories_with_usage($operation = 'edit') {
         global $DB;
         if ($operation == "edit") {
@@ -292,11 +381,15 @@ class courseservice extends \external_api {
     }
 
     /**************************************
-     *
+     * 
      * Progress scanners for teacherview
-     *
+     * 
      **************************************/
 
+    /**
+     * Return value description for scan_grade_progress function
+     * @return external_function_parameters
+     */
     public static function scan_grade_progress_parameters() {
         return new \external_function_parameters( [
             "gradeitemid" => new \external_value(PARAM_INT, 'Grade item ID to scan progress for', VALUE_DEFAULT),
@@ -305,10 +398,20 @@ class courseservice extends \external_api {
         ]);
     }
 
+    /**
+     * Parameter description for scan_grade_progress function
+     * @return \external_description
+     */
     public static function scan_grade_progress_returns() {
         return gradingscanner::structure(VALUE_REQUIRED);
     }
 
+    /**
+     * Scan grade item for progress statistics
+     * @param mixed $gradeitemid Grade item id 
+     * @param mixed $studyplanid Id of studyitem the grade is selected in
+     * @return array
+     */
     public static function scan_grade_progress($gradeitemid, $studyplanid) {
         global $DB;
         // Verify access to the study plan.
@@ -330,6 +433,10 @@ class courseservice extends \external_api {
         return $scanner->model();
     }
 
+    /**
+     * Return value description for scan_completion_progress function
+     * @return \external_description
+     */
     public static function scan_completion_progress_parameters() {
         return new \external_function_parameters( [
             "criteriaid" => new \external_value(PARAM_INT, 'CriteriaID to scan progress for', VALUE_DEFAULT),
@@ -338,10 +445,21 @@ class courseservice extends \external_api {
         ]);
     }
 
+    /**
+     * Parameter description for scan_completion_progress function
+     * @return \external_description
+     */
     public static function scan_completion_progress_returns() {
         return completionscanner::structure(VALUE_REQUIRED);
     }
 
+    /**
+     * Scan criterium for progress statistics
+     * @param mixed $criteriaid Id of criterium
+     * @param mixed $studyplanid Id of studyplan relevant to this criteria
+     * @param mixed $courseid Id of course this cirteria is related to
+     * @return array
+     */
     public static function scan_completion_progress($criteriaid, $studyplanid, $courseid) {
         global $DB;
         // Verify access to the study plan.
@@ -357,6 +475,10 @@ class courseservice extends \external_api {
         return $scanner->model();
     }
 
+    /**
+     * Return value description for scan_badge_progress function
+     * @return \external_description
+     */
     public static function scan_badge_progress_parameters() {
         return new \external_function_parameters( [
             "badgeid" => new \external_value(PARAM_INT, 'Badge to scan progress for', VALUE_DEFAULT),
@@ -365,6 +487,10 @@ class courseservice extends \external_api {
         ]);
     }
 
+    /**
+     * Parameter description for scan_badge_progress function
+     * @return \external_description
+     */
     public static function scan_badge_progress_returns() {
         return new \external_single_structure([
             "total" => new \external_value(PARAM_INT, 'Total number of students scanned'),
@@ -372,6 +498,12 @@ class courseservice extends \external_api {
         ]);
     }
 
+    /**
+     * Scan badge for completion progress statistica 
+     * @param mixed $badgeid ID of the badge
+     * @param mixed $studyplanid ID of the relevant study plan
+     * @return array
+     */
     public static function scan_badge_progress($badgeid, $studyplanid) {
         global $DB;
         // Check access to the study plan.
diff --git a/classes/gradeinfo.php b/classes/gradeinfo.php
index 740fb91..4b49573 100644
--- a/classes/gradeinfo.php
+++ b/classes/gradeinfo.php
@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <https://www.gnu.org/licenses/>.
 /**
- *
+ * Collect, process and display information about gradable items
  * @package    local_treestudyplan
  * @copyright  2023 P.M. Kuipers
  * @license    https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
@@ -29,34 +29,60 @@ require_once($CFG->dirroot.'/course/lib.php');
 
 use core_course\local\repository\caching_content_item_readonly_repository;
 use core_course\local\repository\content_item_readonly_repository;
+use core_course\local\entity\content_item;
 use \grade_item;
 use \grade_scale;
 use \grade_outcome;
 use \core_plugin_manager;
-
+/**
+ * Collect, process and display information about gradable items
+ */
 class gradeinfo {
+    /** @var studyitem */
     private $studyitem = null;
+    /** @var int */
     private $id;
+    /** @var grade_item */
     private $gradeitem;
 
+    /** @var string */
     private $icon;
+    /** @var string */
     private $link;
+    /** @var string */
     private $gradinglink;
+    /** @var grade_scale*/
     private $scale;
+    /** @var grade_outcome*/
     private $outcome;
+    /** @var bool*/
     private $hidden = false;
+    /** @var string */
     private $name;
+    /** @var string */
     private $typename;
+    /** @var int */
     private $section;
+    /** @var int */
     private $sectionorder;
+    /** @var int */
     private $cmid;
+    /** @var int */
     private $coursesort;
 
+    /** @var array */
     private static $contentitems = null;
+    /** @var gradingscanner */
     private $gradingscanner;
 
+    /** @var array */
     private static $sections = [];
 
+    /**
+     * Get the sequence of activities for a given section id
+     * @param mixed $sectionid Id of section
+     * @return int[] Sequence of cms in a section
+     */
     protected static function get_sectionsequence($sectionid) {
         global $DB;
         if (!array_key_exists($sectionid, self::$sections)) {
@@ -65,19 +91,34 @@ class gradeinfo {
         return self::$sections[$sectionid];
     }
 
-    public function get_gradeitem() {
+    /**
+     * Get the grade_item
+     * @return grade_item 
+     */
+    public function get_gradeitem() : grade_item {
         return $this->gradeitem;
     }
-
-    public function get_gradingscanner() {
+    /**
+     * Get the gradingscanner
+     * @return gradingscanner
+     */
+    public function get_gradingscanner() : gradingscanner{
         return $this->gradingscanner;
     }
 
-    public function get_scale() {
+    /**
+     * Get the grade's scale if applicable
+     * @return grade_scale|null
+     */
+    public function get_scale() : ?grade_scale{
         return $this->scale;
     }
 
-    protected static function get_contentitems() {
+    /**
+     * Get content items (activity icons) from the repository
+     * @return content_item[]
+     */
+    protected static function get_contentitems() : array {
         global $PAGE;
         if (empty(static::$contentitems)) {
             $PAGE->set_context(\context_system::instance());
@@ -86,7 +127,12 @@ class gradeinfo {
         return static::$contentitems;
     }
 
-    public static function get_contentitem($name) {
+    /**
+     * Get specific contentitem (activity icons) by name
+     * @param mixed $name Name of content item
+     * @return content_item|null
+     */
+    public static function get_contentitem($name) : ?content_item {
         $contentitems = static::get_contentitems();
         for ($i = 0; $i < count($contentitems); $i++) {
             if ($contentitems[$i]->get_name() == $name) {
@@ -96,7 +142,13 @@ class gradeinfo {
         return null;
     }
 
-    public static function get_coursecontext_by_id($id) {
+    /**
+     * Get a specific course context from grade item id
+     * @param int $id Grade item id
+     * @return context_course
+     * @throws InvalidArgumentException if grade id is not found
+     */
+    public static function get_coursecontext_by_id($id) : \context_course {
         $gi = grade_item::fetch(["id" => $id]);
         if (!$gi || course_module_instance_pending_deletion($gi->courseid, $gi->itemmodule, $gi->iteminstance)) {
             throw new \InvalidArgumentException ("Grade {$id} not found in database");
@@ -104,6 +156,11 @@ class gradeinfo {
         return \context_course::instance($gi->courseid);;
     }
 
+    /**
+     * Create new object around a grade_item 
+     * @param int $id Grade item id of the grade item to use as base
+     * @param studyitem|null $studyitem Studyitem containg the course that references this grade
+     */
     public function __construct($id, studyitem $studyitem = null) {
         global $DB;
         $this->studyitem = $studyitem;
@@ -157,7 +214,11 @@ class gradeinfo {
 
     }
 
-    public function is_selected() {
+    /**
+     * Check if this gradable item is selected in the studyitem
+     * @return bool
+     */
+    public function is_selected() : bool {
         global $DB;
         if ($this->studyitem) {
             // Check if selected for this studyitem.
@@ -170,6 +231,10 @@ class gradeinfo {
         return(false);
     }
 
+    /**
+     * Check if this gradable item is marked required in the studyitem
+     * @return bool
+     */
     public function is_required() {
         global $DB;
         if ($this->studyitem) {
@@ -183,6 +248,11 @@ class gradeinfo {
         return(false);
     }
 
+    /**
+     * Webservice structure for editor info
+     * @param int $value Webservice requirement constant
+     * @return external_single_structure Webservice output structure
+     */
     public static function editor_structure($value = VALUE_REQUIRED) {
         return new \external_single_structure([
             "id" => new \external_value(PARAM_INT, 'grade_item id'),
@@ -199,6 +269,11 @@ class gradeinfo {
         ], 'referenced course information', $value);
     }
 
+    /**
+     * Webservice model for editor info
+     * @param studyitem $studyitem Related studyitem to check for
+     * @return array Webservice data model
+     */
     public function editor_model(studyitem $studyitem = null) {
         $model = [
             "id" => $this->id,
@@ -222,6 +297,11 @@ class gradeinfo {
         return $model;
     }
 
+    /**
+     * Webservice structure for user info
+     * @param int $value Webservice requirement constant
+     * @return external_single_structure Webservice output structure
+     */
     public static function user_structure($value = VALUE_REQUIRED) {
         return new \external_single_structure([
             "id" => new \external_value(PARAM_INT, 'grade_item id'),
@@ -240,6 +320,11 @@ class gradeinfo {
         ], 'referenced course information', $value);
     }
 
+    /**
+     * Webservice model for user info
+	 * @param int $userid ID of user to check specific info for
+     * @return array Webservice data model
+     */
     public function user_model($userid) {
         global $DB;
         $grade = $this->gradeitem->get_final($userid);
@@ -282,7 +367,11 @@ class gradeinfo {
         return $model;
     }
 
-    public function export_model() {
+    /**
+     * Export essential information for export
+     * @return array information model
+     */
+    public function export_model() : array {
         return [
             "name" => $this->name,
             "type" => $this->gradeitem->itemmodule,
@@ -290,6 +379,12 @@ class gradeinfo {
             "required" => $this->is_required(),
         ];
     }
+
+    /**
+     * Import data from exported model into database
+     * @param studyitem $item Studyitem related to this gradable
+     * @param array $model Model data previously exported
+     */
     public static function import(studyitem $item, array $model) {
         if ($item->type() == studyitem::COURSE) {
             $courseid = $item->courseid();
@@ -314,7 +409,13 @@ class gradeinfo {
         }
     }
 
-    public static function list_course_gradables($course, studyitem $studyitem = null) {
+    /**
+     * Get a list if all gradable activities in a given course
+     * @param \stdClass $course Course database record
+     * @param studyitem|null $studyitem Studyitem linked to the course which can be linked to created gradeinfo objects
+     * @return self[] Array of gradeinfo
+     */
+    public static function list_course_gradables($course, studyitem $studyitem = null) : array {
         $list = [];
 
         if (method_exists("\course_modinfo", "get_array_of_activities")) {
@@ -352,7 +453,12 @@ class gradeinfo {
         return $list;
     }
 
-    public static function list_studyitem_gradables(studyitem $studyitem) {
+    /**
+     * List all gradables enabled for a given study item
+     * @param studyitem $studyitem The studyitem to search for
+     * @return self[] Array of gradeinfo
+     */
+    public static function list_studyitem_gradables(studyitem $studyitem) : array{
         global $DB;
         $table = 'local_treestudyplan_gradeinc';
         $list = [];
@@ -378,6 +484,16 @@ class gradeinfo {
         return $list;
     }
 
+    
+    /**
+     * Webservice executor to include grade with studyitem or not.
+     * if both $inclue and $required are false, any existing DB record will be removed
+     * @param int $gradeid ID of the grade_item
+     * @param int $itemid ID of the study item
+     * @param bool $include Select grade_item for studyitem or not
+     * @param bool $required Mark grade_item as required or not
+     * @return success Always returns successful success object 
+     */
     public static function include_grade(int $gradeid, int $itemid, bool $include, bool $required = false) {
         global $DB;
         $table = 'local_treestudyplan_gradeinc';
diff --git a/classes/period.php b/classes/period.php
index 671b24e..b6e6586 100644
--- a/classes/period.php
+++ b/classes/period.php
@@ -26,12 +26,19 @@ defined('MOODLE_INTERNAL') || die();
 require_once($CFG->libdir.'/externallib.php');
 
 class period {
+    /** @var string */
     const TABLE = "local_treestudyplan_period";
     private static $cache = [];
     private static $pagecache = [];
 
+    /**
+     * Holds database record 
+     * @var stdClass
+     */
     private $r; // Holds database record.
+    /** @var int */
     private $id;
+    /** @var studyplanpage */
     private $page;
 
     public function aggregator() {
diff --git a/classes/studyitem.php b/classes/studyitem.php
index 75b9436..214ff04 100644
--- a/classes/studyitem.php
+++ b/classes/studyitem.php
@@ -38,11 +38,18 @@ class studyitem {
     public const TABLE = "local_treestudyplan_item";
 
     private static $studyitemcache = [];
+    /**
+     * Holds database record 
+     * @var stdClass
+     */
     private $r; // Holds database record.
+    /** @var int */
     private $id;
 
     private $courseinfo = null;
     private $studyline;
+    /** @var aggragator[] */
+    /** @var aggragator */
     private $aggregator;
 
     public function context(): \context {
diff --git a/classes/studyitemconnection.php b/classes/studyitemconnection.php
index b43655a..5602bcf 100644
--- a/classes/studyitemconnection.php
+++ b/classes/studyitemconnection.php
@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <https://www.gnu.org/licenses/>.
 /**
- *
+ * Class to manage connection lines between study items
  * @package    local_treestudyplan
  * @copyright  2023 P.M. Kuipers
  * @license    https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
@@ -25,18 +25,38 @@ defined('MOODLE_INTERNAL') || die();
 
 require_once($CFG->libdir.'/externallib.php');
 
+/**
+ * Class to manage connection lines between study items
+ */
 class studyitemconnection {
 
+    /**
+     * Database table for this model 
+     * @var string */
     const TABLE = "local_treestudyplan_connect";
 
+    /**
+     * Holds database record 
+     * @var stdClass
+     */
     private $r;
+    /** @var int */
     private $id;
 
+    /**
+     * Construct new object based on database object
+     * @param stdClass $r Database record
+     */
     protected function __construct($r) {
         $this->r = $r;
         $this->id = $r->id;
     }
 
+    /**
+     * Webservice structure for basic info
+     * @param int $value Webservice requirement constant
+     * @return external_single_structure Webservice output structure
+     */
     public static function structure($value = VALUE_REQUIRED) {
         return new \external_single_structure([
             'id' => new \external_value(PARAM_INT, 'id of connection'),
@@ -45,27 +65,49 @@ class studyitemconnection {
         ], '', $value);
     }
 
+    /**
+     * Webservice model for basic info
+     * @return array Webservice data model
+     */
     public function model() {
         return ['id' => $this->r->id, 'from_id' => $this->r->from_id, 'to_id' => $this->r->to_id];
     }
 
-    public function from_item() {
+
+    /**
+     * Get originating studyitem for this connection
+     */
+    public function from_item() : studyitem {
         return studyitem::find_by_id($this->r->from_id);
     }
 
-    public function to_item() {
+    /**
+     * Get target studyitem for this connection
+     */
+    public function to_item() : studyitem {
         return studyitem::find_by_id($this->r->to_id);
     }
 
-    public function from_id() {
+    /**
+     * Get originating studyitem id for this connection
+     */
+    public function from_id() : int {
         return $this->r->from_id;
     }
 
-    public function to_id() {
+    /**
+     * Get target studyitem id for this connection
+     */
+    public function to_id() :int {
         return $this->r->to_id;
     }
 
-    public static function find_outgoing($itemid) {
+    /**
+     * Get all connections originating at a given studyitem's id
+     * @param int $itemid Id of the studyitem
+     * @return self[]
+     */
+    public static function find_outgoing($itemid) : array {
         global $DB;
         $list = [];
         $connout = $DB->get_records(self::TABLE, ['from_id' => $itemid]);
@@ -75,6 +117,11 @@ class studyitemconnection {
         return $list;
     }
 
+    /**
+     * Get all connections terminating at a given studyitem's id
+     * @param int $itemid Id of the studyitem
+     * @return self[]
+     */
     public static function find_incoming($itemid) {
         global $DB;
         $list = [];
@@ -85,6 +132,11 @@ class studyitemconnection {
         return $list;
     }
 
+    /**
+     * Create a new connection between two study items
+     * @param int $fromid Id of the originating studyitem
+     * @param int $toid Id of the target studyitem
+     */
     public static function connect($fromid, $toid) {
         global $DB;
 
@@ -103,6 +155,11 @@ class studyitemconnection {
         }
     }
 
+    /**
+     * Delete a connection between two study items
+     * @param int $fromid Id of the originating studyitem
+     * @param int $toid Id of the target studyitem
+     */
     public static function disconnect($fromid, $toid) {
         global $DB;
 
@@ -118,6 +175,10 @@ class studyitemconnection {
         }
     }
 
+    /**
+     * Clear all connection to and from a given studyitem
+     * @param int $id Id of the studyitem
+     */
     public static function clear($id) {
         global $DB;
         $DB->delete_records(self::TABLE, ['from_id' => $id]);
diff --git a/classes/studyline.php b/classes/studyline.php
index 09ee6b2..a9a3367 100644
--- a/classes/studyline.php
+++ b/classes/studyline.php
@@ -47,9 +47,16 @@ class studyline {
 
     private static $studylinecache = [];
 
+    /**
+     * Holds database record 
+     * @var stdClass
+     */
     private $r; // Holds database record.
+    /** @var int */
     private $id;
+    /** @var studyplanpage */
     private $page;
+    /** @var studyplan*/
     private $studyplan;
 
     public function context(): \context {
diff --git a/classes/studyplan.php b/classes/studyplan.php
index ce91e8f..a80f0bb 100644
--- a/classes/studyplan.php
+++ b/classes/studyplan.php
@@ -27,14 +27,22 @@ require_once($CFG->libdir.'/externallib.php');
 
 class studyplan {
 
+    /** @var string */
     const TABLE = "local_treestudyplan";
     private static $studyplancache = [];
 
+    /**
+     * Holds database record 
+     * @var stdClass
+     */
     private $r; // Holds database record.
+    /** @var int */
     private $id;
+    /** @var aggragator */
     private $aggregator;
     private $context = null; // Hold context object once retrieved.
     private $linkeduserids = null; // Cache lookup of linked users (saves queries).
+    /** @var studyplanpage[] */
     private $pagecache = null;
 
     public function aggregator() {
diff --git a/classes/studyplanpage.php b/classes/studyplanpage.php
index bdfd3db..3ebd899 100644
--- a/classes/studyplanpage.php
+++ b/classes/studyplanpage.php
@@ -27,11 +27,18 @@ require_once($CFG->libdir.'/externallib.php');
 
 class studyplanpage {
 
+    /** @var string */
     const TABLE = "local_treestudyplan_page";
     private static $cache = [];
 
+    /**
+     * Holds database record 
+     * @var stdClass
+     */
     private $r; // Holds database record.
+    /** @var int */
     private $id;
+    /** @var studyplan*/
     private $studyplan;
 
     public function aggregator() {
diff --git a/classes/teachingfinder.php b/classes/teachingfinder.php
index 2c9e0ba..26bcf0a 100644
--- a/classes/teachingfinder.php
+++ b/classes/teachingfinder.php
@@ -30,6 +30,7 @@ class teachingfinder {
      * Table name used for caching teacher info
      * @var string
      */
+    /** @var string */
     const TABLE = "local_treestudyplan_teachers";