diff --git a/mobile.netbiblio.php b/mobile.netbiblio.php
index e93e973..0d6f5f3 100644
--- a/mobile.netbiblio.php
+++ b/mobile.netbiblio.php
@@ -265,7 +265,14 @@ class NetBiblio extends WebService
     public function GetRandomBooks($number = 100) {
         $sql = "SELECT TOP $number NoticeId
                 FROM Notices
-                WHERE Notices.[NoticeNr] NOT LIKE '%%~%%'
+                WHERE
+                     (
+                        Notices.MediaType1Code='CDD' OR
+                        Notices.MediaType1Code='CDA' OR
+                        Notices.MediaType1Code='CDS'
+                    )
+                    AND Notices.Visible=1
+                    AND Notices.[NoticeNr] NOT LIKE '%%~%%'
                 ORDER BY NEWID();";
         $ids = Connection::execute($sql)->to_array();
         $ids = array_map(function($a) { return $a['NoticeId']; }, $ids);