APA Style

Veblen, T. (1915). The Theory of The Leisure class: An Economc Studies of Institutions (6th ed.). London: The Macmillan Company.

MLA Style

Veblen, Thorstein. "The Theory of The Leisure class: An Economc Studies of Institutions". 6th ed. London: The Macmillan Company, 1915. Text.