diff --git a/src/PurifyServiceProvider.php b/src/PurifyServiceProvider.php
index 666642a..af5f01e 100644
--- a/src/PurifyServiceProvider.php
+++ b/src/PurifyServiceProvider.php
@@ -24,6 +24,7 @@ public function register()
                 // We must autoload the cache manually due to an issue
                 // with the root HTMLPurifier repository. Once this
                 // issue has been resolved, we may remove this.
+                // See: https://github.com/ezyang/htmlpurifier/pull/364
                 spl_autoload_call($cache);
 
                 HTMLPurifier_DefinitionCacheFactory::instance()->register($cache, $cache);