Becker, Carl L. (Carl Lotus), 1873-1945, author
Yale University Press, 1959
Buku Teks
Mackie, Gerry, author
Cambridge University Press, 2003
Buku Teks
Catt, Helena, author
Routledge , 1999
Buku Teks
edited by Richard M. Ketchum
Dutton, 1955
Buku Teks
Ross, Alf, author
Harvard University Press, 1952
Buku Teks