APA (7th ed.) Citation

Gregory, O. B. (1974). Comprehension and study cards (Rev. ed.). Wheaton.

Chicago Style (17th ed.) Citation

Gregory, O. B. Comprehension and Study Cards. Rev. ed. Exeter, Eng.: Wheaton, 1974.

MLA (8th ed.) Citation

Gregory, O. B. Comprehension and Study Cards. Rev. ed. Wheaton, 1974.

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