APA

Lipsey R. G., Chrystal K. . A., . (1995). An Introduction to positive economics. New York: Oxford University Press.

Chicago

Lipsey Richard G, Chrystal K Alec, . 1995. An Introduction to positive economics. New York: Oxford University Press.

Harvard

Lipsey R. G., Chrystal K. . A., . (1995). An Introduction to positive economics. New York: Oxford University Press.

MLA

Lipsey Richard G, Chrystal K Alec, . An Introduction to positive economics. New York: Oxford University Press. 1995.