APA
Samuelson P. A., Samuelson W. & Nordhaus W. D. j. a. (1980). Economics. New York: McGraw-Hill.
Chicago
Samuelson Paul Anthony, Samuelson William and Nordhaus W D joint author. 1980. Economics. New York: McGraw-Hill.
Harvard
Samuelson P. A., Samuelson W. and Nordhaus W. D. j. a. (1980). Economics. New York: McGraw-Hill.
MLA
Samuelson Paul Anthony, Samuelson William and Nordhaus W D joint author. Economics. New York: McGraw-Hill. 1980.