Cooper, Pat, author
Focal Press, 2005
Buku Teks
Corrigan, Timothy
Scott, Foresman and Company, 1989
Buku Teks
Dunn, Dana S., author
Longman, 2011
Buku Teks
Barnet, Sylvan, author
Batsford Academic and Educational, 1985
Buku Teks
Barnet, Sylvan, author
Little, Brown, 1979
Buku Teks