Lindsay, David, author
Longman, 1995
Buku Teks
O`Shea, Robert P., author
Cengage Learning, 2013
Buku Teks
Sholapurkar, Amar A., author
Jaypee Brothers Pvt. Ltd., 2011
Buku Teks
Mahmoud, Shah, author
Betterway, 1992
Buku Referensi
Pechenik, Jan A., author
Pearson Longman, 2007
Buku Teks