Havill, R.L., author
Macmillan, 1975
Buku Teks
Benedict, R. Ralph, author
Prentice-Hall, 1976
Buku Teks
Schuler, Charles A., author
Glencoe McGraw-Hill, 1999
Buku Teks
Brindley, Keith, author
Newnes, 1994
Buku Teks
Duncan, Tom, author
John murray, 1985
Buku Teks