APA (7th ed.) Citation

Koch, R., & Wolpe, B. (1934). Das ABC-Büchlein. Insel-Verl.

Chicago Style (17th ed.) Citation

Koch, Rudolf, and Berthold Wolpe. Das ABC-Büchlein. Leipzig: Insel-Verl, 1934.

MLA (9th ed.) Citation

Koch, Rudolf, and Berthold Wolpe. Das ABC-Büchlein. Insel-Verl, 1934.

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