APA (7th ed.) Citation

Krzywka, R., & De Booter, H. (1957). Ex Bibliotheca Hein De Booter.

Chicago Style (17th ed.) Citation

Krzywka, Ryszard, and Hein De Booter. Ex Bibliotheca Hein De Booter. [S.l.], 1957.

MLA (9th ed.) Citation

Krzywka, Ryszard, and Hein De Booter. Ex Bibliotheca Hein De Booter. 1957.

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