APA (7th ed.) Citation

Kortmann, M., & Haak, O. (1905). Ex Libris Otto Haak.

Chicago Style (17th ed.) Citation

Kortmann, Martin, and Otto Haak. Ex Libris Otto Haak. [Berlin], 1905.

MLA (9th ed.) Citation

Kortmann, Martin, and Otto Haak. Ex Libris Otto Haak. 1905.

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