APA (7th ed.) Citation

Barber, T. X. (1993). The human nature of birds: A scientific discovery with startling implications. Penguin Books.

Chicago Style (17th ed.) Citation

Barber, Theodore Xenophon. The Human Nature of Birds: A Scientific Discovery with Startling Implications. New York: Penguin Books, 1993.

MLA (9th ed.) Citation

Barber, Theodore Xenophon. The Human Nature of Birds: A Scientific Discovery with Startling Implications. Penguin Books, 1993.