McIlwain, Charles Howard, author
Macmillan, 1957
Buku Teks
Hoffman, Ross J.S., author
Littlefield, Adams, 1958
Buku Teks
Sargent, Lyman Tower, author
Wadsworth , 2009
Buku Teks
Kymlicka, Will, author
Clarendon Press, 1990
Buku Teks
Kelly, J. M. (John Maurice), author
Clarendon Press, 2005
Buku Teks