APA استشهاد

Heller, H. (1977). International trade theory and empirical evidence/2nd ed. Prentice hall.

استشهاد بنمط شيكاغو

Heller, H.Robert. International Trade Theory and Empirical Evidence/2nd Ed. New Delhi: Prentice hall, 1977.

MLA استشهاد

Heller, H.Robert. International Trade Theory and Empirical Evidence/2nd Ed. Prentice hall, 1977.