Hunt, Pearson
Richard D. Irwin, [Date of publication not identified]
Buku Teks
Vagts, Detlev F.
Foundation Press, 1973
Buku Teks
Hall, Livingston
West Publishing, 1965
Buku Teks
Tillotson BA., John
Cavendish Publishing Limited, 1996
Buku Teks
Oxford University Press, 1993
Buku Teks SO