APA (7th ed.) Citation

O'Brien, G. (1920). An essay on mediæval economic teaching. Longmans,Green & Co..

Chicago Style (17th ed.) Citation

O'Brien, George. An Essay on Mediæval Economic Teaching. London ; New York: Longmans,Green & Co., 1920.

MLA (9th ed.) Citation

O'Brien, George. An Essay on Mediæval Economic Teaching. Longmans,Green & Co., 1920.

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