Cassidy, Harold G.
Freeman, Cooper & Company , 1970
Buku Teks
Wendy Brown ... [and others] ; edited by Jonathan Ling
Longman Singapore Publishers, 1995
Buku Teks
Beiser, Arthur, author
McGraw-Hill, 1964
Buku Teks
Constant, F. Woodbridge (Frank Woodbridge), 1904-, author
Addison-Wesley, 1967
Buku Teks
Cromer, Alan H., author
McGraw-Hill, 1974
Buku Teks