Cita APA

Samuelson, P. A., & Nordhaus, W. D. (1989). Economics/13e (13th ed.). Mc Graw Hill.

Chicago Edition Citation

Samuelson, Paul A., i William D. Nordhaus. Economics/13e. 13th ed. New York: Mc Graw Hill, 1989.

Cita MLA

Samuelson, Paul A., i William D. Nordhaus. Economics/13e. 13th ed. Mc Graw Hill, 1989.