APA (7th ed.) Citation

National Salesmen's Training Association. (1918). The art and science of selling. National Salesmens Training Association.

Chicago Style (17th ed.) Citation

National Salesmen's Training Association. The Art and Science of Selling. Chicago: National Salesmens Training Association, 1918.

MLA (9th ed.) Citation

National Salesmen's Training Association. The Art and Science of Selling. National Salesmens Training Association, 1918.