Gillin, John Philip, author
University of Pittsburgh Press, 1969
Buku Teks
Kottak, Conrad Phillip, 1942-, author
McGraw-Hill Education cop, 2015
Buku Teks
Barnes, Robert H., author
2004
Artikel Jurnal
Eckhardt, Robert B., author
McGraw-Hill, 1979
Buku Teks
Stevenson, Leslie Forster, author
Oxford University Press, 2012
Buku Teks