Cita APA (7a ed.)

Voegelin, C. F., & Voegelin, F. M. (1978). Classification and index of the world's languages (2nd printing.). Elsevier.

Cita Chicago Style (17a ed.)

Voegelin, Charles F., y Florence M. Voegelin. Classification and Index of the World's Languages. 2nd printing. New York [etc.]: Elsevier, 1978.

Cita MLA (9a ed.)

Voegelin, Charles F., y Florence M. Voegelin. Classification and Index of the World's Languages. 2nd printing. Elsevier, 1978.