Jenks, Edward
John Murray, 1933
Buku Teks
Morrison, Wayne, author
Cavendish Publishing Limited, 2000
Buku Teks
McCoubrey, Hilaire, author
Black Stone Press Limited, 1999
Buku Teks
Kelly, J. M. (John Maurice), author
Clarendon Press, 2005
Buku Teks
Carpenter, William Seal
Appleton-Century-Crotts,Inc., 1958
Buku Teks