diff --git a/php/rest/getParameterList.php b/php/rest/getParameterList.php
index 348abc5..3f2d257 100644
--- a/php/rest/getParameterList.php
+++ b/php/rest/getParameterList.php
@@ -6,8 +6,8 @@
  * @apiName getParameterList
  * @apiGroup webservices
  *
- * @apiParam {String} userID Identifier of the user in AMDA.
- * @apiParam {String} password password of the user in AMDA.
+ * @apiParam {String} [userID] Identifier of the user in AMDA (*mandatory for user owned data*)
+ * @apiParam {String} [password] Password of the user in AMDA (*mandatory for user owned data*)
  *
  * @apiSuccess {String} success `true`
  * @apiSuccess {String} URL of the XML file, which contains the list of derived parameters and parameters in AMDA
--
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