Barlow, Patricia
Kluwer Law & Taxation, 1988
Buku Teks
Fugate, Wilbur L.
Little, Brown, 1982
Buku Teks
Taussig, Frank William
Harvard University Press, 1934
Buku Teks
Seward, William W.
Frederick Fell, 1963
Buku Teks
Lewis, William Arthur, 1915-
University of Ghana by the Ghana Pub, 1971
Buku Teks