edited by Ralph E. Pumphrey and Muriel W. Pumphrey
Columbia University Press, 1961
Buku Teks
Farley, John E., author
Prentice-Hall, 1987
Buku Teks
Kelly, Alfred H.
W.W Norton & Company Inc., c 19
Buku Teks
Kelly, Alfred H.
W.W. Norton & Company. Inc., 1963
Buku Teks
Kelly, Alfred H.
W.W. Norton & Company, 1955
Buku Teks