APA (7th ed.) Citation

Ott, N., & Janssens, P. (1968). Piet Janssens Ex Libris.

Chicago Style (17th ed.) Citation

Ott, Norbert, and Piet Janssens. Piet Janssens Ex Libris. [S.l, 1968.

MLA (9th ed.) Citation

Ott, Norbert, and Piet Janssens. Piet Janssens Ex Libris. 1968.

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