Wojtowicz, Robert, author
Cambridge University Press, 1998
Buku Teks
edited by F. Stuart Chapin and Shirley F. Weiss
John Wiley & Sons, 1962
Buku Teks
Green, Constance McLaughlin, 1897-1975
Harper & Row, Publishers, 1965
Buku Teks
Barck, Oscar Theodore, Jr., 1902-1993, author
Macmillan, 1965
Buku Teks
Link, Arthur S., author
Alfreda A. Knopf, 1955
Buku Teks