diff --git a/mod/workshop/allocation/manual/renderer.php b/mod/workshop/allocation/manual/renderer.php
index a99636fa9d4..722f47a922e 100644
--- a/mod/workshop/allocation/manual/renderer.php
+++ b/mod/workshop/allocation/manual/renderer.php
@@ -58,7 +58,7 @@ class moodle_mod_workshop_allocation_manual_renderer extends moodle_renderer_bas
      * @param object message to display
      * @return string html code
      */
-    public function display_allocations(workshop $workshop, &$peers, $hlauthorid=null, $hlreviewerid=null, $msg=null) {
+    public function display_allocations(workshop $workshop, $peers, $hlauthorid=null, $hlreviewerid=null, $msg=null) {
 
         $wsoutput = $this->page->theme->get_renderer('mod_workshop', $this->page);
         if (empty($peers)) {
@@ -125,7 +125,7 @@ class moodle_mod_workshop_allocation_manual_renderer extends moodle_renderer_bas
      * @param array $peers           objects with properties to display picture and fullname
      * @return string html code
      */
-    protected function reviewers_of_participant(object $user, workshop $workshop, &$peers) {
+    protected function reviewers_of_participant(object $user, workshop $workshop, $peers) {
         $o = '';
         if (is_null($user->submissionid)) {
             $o .= $this->output->output_tag('span', array('class' => 'info'), get_string('nothingtoreview', 'workshop'));
@@ -171,7 +171,7 @@ class moodle_mod_workshop_allocation_manual_renderer extends moodle_renderer_bas
      * @param array $peers           objects with properties to display picture and fullname
      * @return string html code
      */
-    protected function reviewees_of_participant(object $user, workshop $workshop, &$peers) {
+    protected function reviewees_of_participant(object $user, workshop $workshop, $peers) {
         $o = '';
         if (is_null($user->submissionid)) {
             $o .= $this->output->container(get_string('withoutsubmission', 'workshop'), 'info');
@@ -215,7 +215,7 @@ class moodle_mod_workshop_allocation_manual_renderer extends moodle_renderer_bas
      * @param array $users array of users or array of groups of users
      * @return array of options to be passed to {@link html_select::make_ popup_form()}
      */
-    protected function users_to_menu_options(&$users, array $exclude) {
+    protected function users_to_menu_options($users, array $exclude) {
         $options = array(); // to be returned
         foreach ($users as $user) {
             if (!isset($exclude[$user->id])) {
diff --git a/mod/workshop/allocation/random/simpletest/testallocator.php b/mod/workshop/allocation/random/simpletest/testallocator.php
index b93c0a2427b..0a73e3228de 100644
--- a/mod/workshop/allocation/random/simpletest/testallocator.php
+++ b/mod/workshop/allocation/random/simpletest/testallocator.php
@@ -54,7 +54,7 @@ class testable_workshop_random_allocator extends workshop_random_allocator {
         return parent::get_element_with_lowest_workload($workload);
     }
     public function filter_current_assessments(&$newallocations, $assessments) {
-        return parent::filter_current_assessments($newallocations, $assessments);
+        return parent::filter_current_assessments(&$newallocations, $assessments);
     }
 }
 
diff --git a/mod/workshop/grading/assessment_form.php b/mod/workshop/grading/assessment_form.php
index 10569256e2f..75dff9836d2 100644
--- a/mod/workshop/grading/assessment_form.php
+++ b/mod/workshop/grading/assessment_form.php
@@ -62,13 +62,13 @@ class workshop_assessment_form extends moodleform {
 
         $buttonarray = array();
         if ($this->mode == 'preview') {
-            $buttonarray[] = &$mform->createElement('submit', 'backtoeditform', get_string('backtoeditform', 'workshop'));
+            $buttonarray[] = $mform->createElement('submit', 'backtoeditform', get_string('backtoeditform', 'workshop'));
         }
         if ($this->mode == 'assessment') {
-            $buttonarray[] = &$mform->createElement('submit', 'saveandcontinue', get_string('saveandcontinue', 'workshop'));
-            $buttonarray[] = &$mform->createElement('submit', 'saveandclose', get_string('saveandclose', 'workshop'));
+            $buttonarray[] = $mform->createElement('submit', 'saveandcontinue', get_string('saveandcontinue', 'workshop'));
+            $buttonarray[] = $mform->createElement('submit', 'saveandclose', get_string('saveandclose', 'workshop'));
         }
-        $buttonarray[] = &$mform->createElement('cancel');
+        $buttonarray[] = $mform->createElement('cancel');
         $mform->addGroup($buttonarray, 'buttonar', '', array(' '), false);
         $mform->closeHeaderBefore('buttonar');
     }
diff --git a/mod/workshop/grading/edit_form.php b/mod/workshop/grading/edit_form.php
index a74e8e0aad5..daa75f3d1e1 100644
--- a/mod/workshop/grading/edit_form.php
+++ b/mod/workshop/grading/edit_form.php
@@ -70,10 +70,10 @@ class workshop_edit_strategy_form extends moodleform {
         //}
 
         $buttonarray = array();
-        $buttonarray[] = &$mform->createElement('submit', 'saveandcontinue', get_string('saveandcontinue', 'workshop'));
-        $buttonarray[] = &$mform->createElement('submit', 'saveandpreview', get_string('saveandpreview', 'workshop'));
-        $buttonarray[] = &$mform->createElement('submit', 'saveandclose', get_string('saveandclose', 'workshop'));
-        $buttonarray[] = &$mform->createElement('cancel');
+        $buttonarray[] = $mform->createElement('submit', 'saveandcontinue', get_string('saveandcontinue', 'workshop'));
+        $buttonarray[] = $mform->createElement('submit', 'saveandpreview', get_string('saveandpreview', 'workshop'));
+        $buttonarray[] = $mform->createElement('submit', 'saveandclose', get_string('saveandclose', 'workshop'));
+        $buttonarray[] = $mform->createElement('cancel');
         $mform->addGroup($buttonarray, 'buttonar', '', array(' '), false);
         $mform->closeHeaderBefore('buttonar');
     }