Perhaps you should try some spelling variations:
stadler studien » realer studien, stifter studien, studie studien
tests stadler » tests stable, 21st stadler, teste stadien
ii literature » ii literatur, i literature, vii literatur
filosofia ii » filosofia di, filosofica di, filosofia de
3 filosofia » e filosofia, a filosofia, y filosofia
studien 3 » studien _, studien 4, studien 5