Lumsden, k. (1970). Microeconomics: A programmed book (2nd ed.). Prentice-Hall.
Cita Chicago (17th ed.)Lumsden, keith. Microeconomics: A Programmed Book. 2nd ed. Englewood Cliffs: Prentice-Hall, 1970.
Cita MLA (9th ed.)Lumsden, keith. Microeconomics: A Programmed Book. 2nd ed. Prentice-Hall, 1970.
Atenció: Aquestes cites poden no estar 100% correctes.