diff --git a/modules/system/system.api.php b/modules/system/system.api.php
index 802f470..124b89b 100644
--- a/modules/system/system.api.php
+++ b/modules/system/system.api.php
@@ -2105,11 +2105,13 @@ function hook_permission() {
  * specify how a particular render array is to be rendered as HTML (this is
  * usually the case if the theme function is assigned to the render array's
  * #theme property), or they return the HTML that should be returned by an
- * invocation of theme().
+ * invocation of theme(). See @link http://http://drupal.org/node/933976 Using
+ * the theme layer (Drupal 7.x) @endlink for more information on how to
+ * implement theme hooks that will be used by theme().
  *
  * The following parameters are all optional.
  *
- * @param array $existing
+ * @param $existing
  *   An array of existing implementations that may be used for override
  *   purposes. This is primarily useful for themes that may wish to examine
  *   existing implementations to extract data (such as arguments) so that
@@ -2131,7 +2133,7 @@ function hook_permission() {
  *   The directory path of the theme or module, so that it doesn't need to be
  *   looked up.
  *
- * @return array
+ * @return
  *   An associative array of theme hook information. The keys on the outer
  *   array are the internal names of the hooks, and the values are arrays
  *   containing information about the hook. Each information array must contain