Maine, Henry Sumner, 1822-1888, author
University of Arizona Press, 1986
Buku Teks
Field, G. Lowell, author
Buku Teks
Wicks, Rollo E.
N.Y. State Univ. of New York , 1958
Buku Teks
Berger, Morroe, author
D. Van Nostrand, 1954
Buku Teks
Udy, Stanley H., 1928-, author
Prentice-Hall, 1970
Buku Teks