Katheleen Norris
Houghton Mifflin, 2001
Buku Teks
Russell, Bertrand, 1872-1970, author
Routledge, 1998
Buku Teks
edited by Peter G. Gowing and William Henry Scott
New day, 1971
Buku Teks
Bierstedt, Robert, author
McGraw-Hill, 1974
Buku Teks
Arnold, Matthew
Oxford University Press, 1925
Buku Teks