APA (7th ed.) Citation

Christie, A. (1984). The big four (1st edition.). Berkley Books.

Chicago Style (17th ed.) Citation

Christie, Agatha. The Big Four. 1st edition. New York: Berkley Books, 1984.

MLA (9th ed.) Citation

Christie, Agatha. The Big Four. 1st edition. Berkley Books, 1984.

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