Kubba, Sam
Buth-Helnemn, 2012
Buku Teks SO
Gang Da Press, 2011
Buku Referensi
Frederick S. Merritt and Jonathan T. Ricketts, editor
McGraw-Hill, Inc, 1994
Buku Referensi
Hall, Fred
Butterworth-Heinemann, 2003
Buku Teks SO
edited by Richard N. White, Charles G. Salmon
John Wiley & Sons, 1987
Buku Referensi