Oppenheim, S. Chesterfield
Little, Brown & Co., 1971
Buku Teks
Glen E.Weston
Little,Brown and Company, 1971
Buku Teks
Weston, Glen E.
West Publishing CO, 1992
Buku Teks SO
Weston, Glen E.
West Publishing CO, 1992
Buku Teks SO
McCormick, Charles T. (Charles Tilford), 1889-1963
Foundation Press, 1976
Buku Teks