Bruns, Ramon O., author
Burgess Publishing Company, 1974
Buku Teks
Fuentes, Agustin, author
McGraw-Hill, 2012
Buku Teks
Leith, John D., author
Burgess, 1970
Buku Teks
edited by Deborah Antai-Otong
W.B. Saunders, 1995
Buku Teks
Maheshwari, B.L.
Tata McGraw-Hill, 1990
Buku Teks