diff --git a/core/modules/file/file.module b/core/modules/file/file.module
index b7d2f3c..01ea035 100644
--- a/core/modules/file/file.module
+++ b/core/modules/file/file.module
@@ -957,22 +957,68 @@ function file_icon_map($file) {
 /**
  * Gets a list of references to a file.
  *
+ * Returns a list of entities or revisions that reference a file. A file
+ * should not be deleted if still referenced.
+ *
  * @param $file
  *   A file object.
  * @param $field
- *   (optional) A field array to be used for this check. If given, limits the
- *   reference check to the given field.
+ *   (optional) A field array that limits the reference check to the given
+ *   field.
  * @param $age
  *   (optional) A constant that specifies which references to count. Use
  *   FIELD_LOAD_REVISION to retrieve all references within all revisions or
  *   FIELD_LOAD_CURRENT to retrieve references only in the current revisions.
- * @param $field_type
+ *   Default is FIELD_LOAD_REVISION.
+ * @param string $field_type
  *   (optional) The name of a field type. If given, limits the reference check
  *   to fields of the given type.
  *
  * @return
- *   An integer value.
- */
+ *   An array of references. If $age is FIELD_LOAD_CURRENT, they are entity
+ *   IDs. If $age is FIELD_LOAD_REVISION, they are revision IDs. Example of
+ *   entity_id returned with FIELD_LOAD_CURRENT:
+ *   @code
+ *   $references = array(
+ *     $field_name => array(
+ *       $entity_type => array(
+ *         $entity_id (nid, 123) => array(
+ *           'nid' => 123,
+ *           'vid' => 124,
+ *           'type' => 'blog',
+ *         ),
+ *       ),
+ *     ),
+ *   );
+ *   @endcode
+ *   Example of revision_id returned with FIELD_LOAD_REVISION:
+ *   @code
+ *   $references = array(
+ *     $field_name => array(
+ *       $entity_type => array(
+ *         $revision_id (vid, 124) => array(
+ *           'nid' => 123,
+ *           'vid' => 124,
+ *           'type' => 'blog',
+ *         ),
+ *       ),
+ *     ),
+ *   );
+ *   @endcode
+ *   Example of revision_id returned if field has been specified:
+ *   @code
+ *   $references = array(
+ *      $entity_type => array(
+ *        $revision_id (vid, 124) => array(
+ *          'nid' => 123,
+ *          'vid' => 124,
+ *          'type' => 'blog',
+ *        ),
+ *      ),
+ *    ),
+ *   );
+ *   @endcode
+*/
 function file_get_file_references($file, $field = NULL, $age = FIELD_LOAD_REVISION, $field_type = 'file') {
   $references = drupal_static(__FUNCTION__, array());
   $fields = isset($field) ? array($field['field_name'] => $field) : field_info_fields();