APA (7th ed.) Citation

Koppisch, O., & Freyer, W. (1906). Ex Libris Wilhelm Freyer.

Chicago Style (17th ed.) Citation

Koppisch, Oskar, and Wilhelm Freyer. Ex Libris Wilhelm Freyer. [S. l, 1906.

MLA (9th ed.) Citation

Koppisch, Oskar, and Wilhelm Freyer. Ex Libris Wilhelm Freyer. 1906.

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