एपीए उद्धरण

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

शिकागो स्टाइल उद्धरण

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

एमएलए उद्धरण

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