APA Style

Gregory, R. (1971). The origins of American intervention in the First World War / Ross Gregory (1). New York: W. W. Norton & Company..

MLA Style

Gregory, Ross. "The origins of American intervention in the First World War / Ross Gregory". 1 New York: W. W. Norton & Company., 1971. Textbook ห้องสมุดทั่วไป.