APA

Porkess R., Erlich E., . (1991). The Harper Collins dictionary of statistics. New York: Harper Collins.

Chicago

Porkess Roger, Erlich Eugene, . 1991. The Harper Collins dictionary of statistics. New York: Harper Collins.

Harvard

Porkess R., Erlich E., . (1991). The Harper Collins dictionary of statistics. New York: Harper Collins.

MLA

Porkess Roger, Erlich Eugene, . The Harper Collins dictionary of statistics. New York: Harper Collins. 1991.