APA
Gray A., . (1931). Development of economic doctrine. London: Longmans Green & Company.
Chicago
Gray Alexander, . 1931. Development of economic doctrine. London: Longmans Green & Company.
Harvard
Gray A., . (1931). Development of economic doctrine. London: Longmans Green & Company.
MLA
Gray Alexander, . Development of economic doctrine. London: Longmans Green & Company. 1931.