Cita APA (7a ed.)

Willems, J., Spillemaeckers, R., Ryckx, W., & Willems, R. (1997). Landschappen in Belgie͏̈ (4. dr.). De Sikkel.

Cita Chicago Style (17a ed.)

Willems, J., R. Spillemaeckers, W. Ryckx, y R. Willems. Landschappen in Belgie͏̈. 4. dr. Oostmalle: De Sikkel, 1997.

Cita MLA (9a ed.)

Willems, J., et al. Landschappen in Belgie͏̈. 4. dr. De Sikkel, 1997.