Etter, Delores Maria, 1947-
Prentice-Hall, 2002
Buku Teks
Palm III, Wiliam J.
Mc Graw Hill, 2011
Buku Teks
Gilat, Amos
John Wiley & Sons, 2011
Buku Teks
Devijver, Pierre A.
Prentice-Hall International, 1982
Buku Teks SO
Foley, Greg, 1963-, (author.)
Cambridge University Press, 2013
Buku Teks