APA (7th ed.) Citation

Welten, H. (1921). Biologische Probleme. Velhagen & Klasing.

Chicago Style (17th ed.) Citation

Welten, Heinz. Biologische Probleme. Bielefeld [u.a.]: Velhagen & Klasing, 1921.

MLA (9th ed.) Citation

Welten, Heinz. Biologische Probleme. Velhagen & Klasing, 1921.

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