Alley, Rewi, 1897-1987, author
New World Press, 1961
Buku Teks
Smedley, Agnes, author
Vanguard Press, 1933
Buku Teks
Richman, Barry M.
Random House , 1969
Buku Teks
Cressey, Geoge Babcock, author
McGraw-Hill, 1934
Buku Teks
Eckstein, Alexander, author
Cambridge University Press, 1979
Buku Teks