APA (7th ed.) Citation

Hummel, K. (1925). Geschichte der Geologie. de Gruyter.

Chicago Style (17th ed.) Citation

Hummel, Karl. Geschichte Der Geologie. Berlin [u.a.]: de Gruyter, 1925.

MLA (9th ed.) Citation

Hummel, Karl. Geschichte Der Geologie. de Gruyter, 1925.

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