Barnett, Harold J., author
John Hopkins Press, 1963
Buku Teks
Meier, Richard L., author
The Massachusett Institute of Technology, 1974
Buku Teks
Xenos, Nicholas
Routledge, 1989
Buku Teks
Brown, Harrison
The Viking Press , 1963
Buku Teks
Savory, Allan
Island Press, 1988
Buku Teks