Davenport, S.J.
Washington, DC: United States Department of the Interior, 1954
Buku Teks
De Nevers, Noel, 1932-
McGraw-Hill, 1995
Buku Teks
edited by David R. Patrick
Van Nostrand Reinhold, 1994
Buku Referensi
edited by Albert Parker
McGraw-Hill, 1978
Buku Referensi
Colbeck, I. (Ian)
Elsevier, 1994
Buku Teks