edited by Willy Sellekaerts
Macmillan, 1974
Buku Teks
Gipson, Carolyn R., author
McGraw-Hill, 1994
Buku Referensi
Root, Franklin R., author
Sout-Western, 1966
Buku Teks
Vandezande, Niels, author
Intersentia, 2018
eBooks
Billah, Mohd. Ma`sum, author
Sweet & Maxwell, 2007
Buku Teks