APA (7th ed.) Citation

Ducks Unlimited. (1973). Ducks Unlimited's wing watcher's guide: A guide to field identification of waterfowl. [publisher not identified].

Chicago Style (17th ed.) Citation

Ducks Unlimited. Ducks Unlimited's Wing Watcher's Guide: A Guide to Field Identification of Waterfowl. Chicago : Ducks Unlimited: [publisher not identified], 1973.

MLA (9th ed.) Citation

Ducks Unlimited. Ducks Unlimited's Wing Watcher's Guide: A Guide to Field Identification of Waterfowl. [publisher not identified], 1973.