Rob, Peter, author
Course Technology, 2002
Buku Teks
Prothro, Vivian C., author
Mason/Petro-Charter Pub., 1976
Buku Teks
Rob, Peter, author
Wadsworth, 1993
Buku Teks
compiled by David R. Hampton
Prentince-Hall of India, 1979
Buku Teks
Connolly, Thomas M., author
Addison-Wesley , 2005
Buku Teks