Americana Corporation, 1980
Buku Referensi
Aronson, Joseph, author
Clarkson Potter, 1965
Buku Referensi
Unsworth, Walt, 1928-, author
Penguin, 1977
Buku Referensi
Barnard, Robert, author
Oxford : Blackwel, 2013
Buku Referensi
editor, Donald M. Borchert
Macmilan, 1996
Buku Referensi