Gaya APA

Strahler, A, N., Strahler, A, H. (1984). Elements of physical geography (3rd ed.). New York: John Wiley & Sons, Inc..

Gaya MLA

Strahler, Arthur, N.., Strahler, Alan, H.. "Elements of physical geography". 3rd ed. New York: John Wiley & Sons, Inc., 1984. Text.