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.