Παραπομπή APA

Helliwell,J F. (1976). Aggregate investment: Selected readings. Penguin Education.

Παραπομπή Chicago Style

Helliwell,J F. Aggregate Investment: Selected Readings. England: Penguin Education, 1976.

Παραπομπή MLA

Helliwell,J F. Aggregate Investment: Selected Readings. Penguin Education, 1976.