APA (7th ed.) Citation

Ettlinger, K., & Sturtzkopf, C. (1923). Karlchen-Album. Georg Müller.

Chicago Style (17th ed.) Citation

Ettlinger, Karl, and Carl Sturtzkopf. Karlchen-Album. München: Georg Müller, 1923.

MLA (9th ed.) Citation

Ettlinger, Karl, and Carl Sturtzkopf. Karlchen-Album. Georg Müller, 1923.

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