Aggarwal, Bharat B
Sterling Publishing, 2011
Buku Teks SO
Hutton, Wendy
Periplus, 1997
Buku Referensi
Kumar, Vijay
Sterling Publishing, 2010
Buku Teks SO
Skelly, Carole J.
Garland Publishing, 1994
Buku Referensi
Tenney, Louise
Woodland Publishing, 1995
Buku Teks SO