MLA

Peeters, Carel, and Séra de Vriendt. Linguistics In Belgium. Brussel: Didier, 1977.

APA

Peeters, C., & de Vriendt, S. (1977). Linguistics in Belgium. Brussel: Didier.

Chicago

Peeters, Carel, ed., and Séra de Vriendt ed. Linguistics In Belgium. Brussel: Didier, 1977.