एपीए उद्धरण

Ward,Barbara. (1979). Progress for a small planet. Penguin Books.

शिकागो स्टाइल उद्धरण

Ward,Barbara. Progress for a Small Planet. England: Penguin Books, 1979.

एमएलए उद्धरण

Ward,Barbara. Progress for a Small Planet. Penguin Books, 1979.