APA (7th ed.) Citation

Acker, W. V. The Nine-Square Grid. Imprensa da Universidade de Coimbra.

Chicago Style (17th ed.) Citation

Acker, Wouter Van. The Nine-Square Grid. Imprensa da Universidade de Coimbra.

MLA (9th ed.) Citation

Acker, Wouter Van. The Nine-Square Grid. Imprensa da Universidade de Coimbra.

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