Trattner, Walter I.
Free Press, 1984
Buku Teks
Cohen, Nathan Edward
Holt, Rinehart and Winston, 1958
Buku Teks
edited by Ralph E. Pumphrey and Muriel W. Pumphrey
Columbia University Press, 1961
Buku Teks
Lafrance, Arthur B.
West Publishing Company, 1979
Buku Teks
Davis, Janet M.
Oxford University Press, 2016
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