Παραπομπή APA

Heilbroner, R. L. (1968). The Economic Problem. Prentice-Hall of India.

Παραπομπή Chicago Style

Heilbroner, Robert L. The Economic Problem. New Jersey: Prentice-Hall of India, 1968.

Παραπομπή MLA

Heilbroner, Robert L. The Economic Problem. Prentice-Hall of India, 1968.