APA (7th ed.) Citation

Onion & Friedrichsen. (1966). The Oxford dictionary of English etymology. Clarendon Press.

Chicago Style (17th ed.) Citation

Onion and Friedrichsen. The Oxford Dictionary of English Etymology. Oxford: Clarendon Press, 1966.

MLA (8th ed.) Citation

Onion and Friedrichsen. The Oxford Dictionary of English Etymology. Clarendon Press, 1966.