APA (7th ed.) Citation

Marckwardt, A. H., Walcott, F. G., & Leonard, S. A. (1938). Facts about current English usage. D. Appleton-Century company, incorporated.

Chicago Style (17th ed.) Citation

Marckwardt, Albert H., Fred G. Walcott, and Sterling Andrus Leonard. Facts About Current English Usage. New York, London: D. Appleton-Century company, incorporated, 1938.

MLA (9th ed.) Citation

Marckwardt, Albert H., et al. Facts About Current English Usage. D. Appleton-Century company, incorporated, 1938.