APA (7th ed.) Citation

Felix & Theo. (1998). Barbara (3. [Dr.].). Langenscheidt.

Chicago Style (17th ed.) Citation

Felix and Theo. Barbara. 3. [Dr.]. Berlin ; München [u.a.]: Langenscheidt, 1998.

MLA (9th ed.) Citation

Felix and Theo. Barbara. 3. [Dr.]. Langenscheidt, 1998.