APA

Beck W. S., Liem K. F. & Simpson G. G. (1991). Life: an introduction to biology. New York: Harper Collins Publishers.

Chicago

Beck William Samson, Liem Karel F and Simpson George Gaylord. 1991. Life: an introduction to biology. New York: Harper Collins Publishers.

Harvard

Beck W. S., Liem K. F. and Simpson G. G. (1991). Life: an introduction to biology. New York: Harper Collins Publishers.

MLA

Beck William Samson, Liem Karel F and Simpson George Gaylord. Life: an introduction to biology. New York: Harper Collins Publishers. 1991.