एपीए उद्धरण

Beekmann, P. (1971). History of Pi. St. Martin's Press.

शिकागो स्टाइल उद्धरण

Beekmann, Petr. History of Pi. New York: St. Martin's Press, 1971.

एमएलए उद्धरण

Beekmann, Petr. History of Pi. St. Martin's Press, 1971.