The University of Michigan, 1975
Buku Teks
Boston, 1957
Buku Teks
Brecht, Bertolt, 1898-1956, author
Eyre Methuen, 1979
Buku Teks
Lontar Foundation, 1993
Buku Teks
Robert Maynard Hutchins, editor in chief
Encyclopaedia Britannica, Inc., 1952
Buku Referensi