APA (7th ed.) Citation

Voegelin, C. F., & Voegelin, F. M. (1977). Classification and index of the world's languages / (by) C.F. and F.M. Voegelin. Elsevier.

Chicago Style (17th ed.) Citation

Voegelin, Charles Frederick, and Florence Marie Voegelin. Classification and Index of the World's Languages / (by) C.F. and F.M. Voegelin. New York ; Oxford (etc.): Elsevier, 1977.

MLA (9th ed.) Citation

Voegelin, Charles Frederick, and Florence Marie Voegelin. Classification and Index of the World's Languages / (by) C.F. and F.M. Voegelin. Elsevier, 1977.

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