/**
  * Gets the header of the report
  *
  * @param array|string $selected_sources
  * @return array
  */
 public function getHeader($selected_sources)
 {
     $result_list = array();
     $results = DLEApi::getResults($this->document_guid);
     foreach ($results as $result) {
         $result_list[$result->guid] = array('percentage' => $result->percentage);
         if ($this->mode == 'detailed') {
             $result_list[$result->guid]['input'] = array('type' => 'radio', 'checked' => $result->guid == $selected_sources, 'value' => $result->guid, 'name' => 'diff');
         } else {
             $result_list[$result->guid]['input'] = array('type' => 'checkbox', 'checked' => in_array($result->guid, $selected_sources), 'value' => $result->guid, 'name' => 'guids_use[]');
         }
         $result_list[$result->guid]['source'] = array('title' => $result->type == 'local' ? sprintf(DLEApi::getText('document_written_by'), $result->student_name, $result->student_number) : $result->url, 'link' => $result->type == 'local' ? ($document_id = DLEApi::checkDocumentExists($result->original_guid)) ? DLEApi::getURL($document_id) : false : $result->url);
     }
     return $result_list;
 }