Oppenheim, S. Chesterfield
Little, Brown , 1971
Buku Teks
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
McCormick, Charles T. (Charles Tilford), 1889-1963, author
Foundation Press, 1976
Buku Teks