APA (7th ed.) Citation

Lernzirkel USA. Klett-Perthes.

Chicago Style (17th ed.) Citation

Lernzirkel USA. Gotha [u.a.]: Klett-Perthes.

MLA (9th ed.) Citation

Lernzirkel USA. Klett-Perthes.

Warning: These citations may not always be 100% accurate.