APA استشهاد

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

استشهاد بنمط شيكاغو

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

MLA استشهاد

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