Heller, H. R. (1973). International trade: Theory and empirical evidence (2d ed.). Prentice-Hall.
Chicago Style aipamenaHeller, H. Robert. International Trade: Theory and Empirical Evidence. 2d ed. Englewood Cliffs, N.J.: Prentice-Hall, 1973.
MLA aipamenaHeller, H. Robert. International Trade: Theory and Empirical Evidence. 2d ed. Prentice-Hall, 1973.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.