Citazione Stile APA (7a Edizione)

Helbling, R. E. (1983). First-year German (3. ed.). Holt, Rinehart and Winston.

Citazione stile Chigago Style (17a edizione)

Helbling, Robert E. First-year German. 3. ed. New York [u.a.]: Holt, Rinehart and Winston, 1983.

Citatione MLA (9a ed.)

Helbling, Robert E. First-year German. 3. ed. Holt, Rinehart and Winston, 1983.