Sturrock, Ford, author
Pitman, 1982
Buku Teks
Kay, Ronald D.
McGraw-Hill, 2012
Buku Teks
Hopkins, John A., author
Iowa State University Press, 1962
Buku Teks
Heady, Earl O., author
Prentice-Hall, 1954
Buku Teks
Hansen, Don R., author
South-Western College Publishing, 2000
Buku Teks