APA (7th ed.) Citation

Klemm, P. (1968). Ernst Haeckel. Urania Verlag.

Chicago Style (17th ed.) Citation

Klemm, Peter. Ernst Haeckel. Leipzig: Urania Verlag, 1968.

MLA (8th ed.) Citation

Klemm, Peter. Ernst Haeckel. Urania Verlag, 1968.

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