Cobb. (2006). International Economics (5th ed.). McGraw–Hill Irwin. . Case, Karl E. & Fair, Ray C. (1999). Principles of Economics (5th ed.). Prentice-Hall. . External links "The Heckscher-Ohlin Trade Model." - Heckscher-Ohlin Model. Web. 16 March 2015. Economics theorems International trade theory