Strahler, Arthur N., author
John Wiley & Sons, 1973
Buku Teks
Van Riper, Joseph E., author
McGraw-Hill, 1971
Buku Teks
Knapp, Brian, author
Longman House, 1992
Buku Teks
Moore, W. G.
Penguin, 1974
Buku Referensi
Mather, P.M., author
John Wiley & Sons, 1976
Buku Teks