Παραπομπή APA

Mentrup, W. (1968). Rules of German Orthography. Bibliographisches Institut.

Παραπομπή Chicago Style

Mentrup, Wolfgang. Rules of German Orthography. Zurich: Bibliographisches Institut, 1968.

Παραπομπή MLA

Mentrup, Wolfgang. Rules of German Orthography. Bibliographisches Institut, 1968.