Zelinsky, Marilyn
McGraw-Hill, 1997
Buku Teks SO
edited by Michael Hulse, David Kennedy and David Morley
Bloodaxe Books, 1993
Buku Teks
Flynn, John E.
McGraw-Hill, 1966
Buku Teks
Fulmer, Robert M.
Macmillan, 1974
Buku Teks
Jenks, Edward
John Murray, 1933
Buku Teks