Gordon, Gerald
Yale University Press, 1966
Buku Teks
Wright, Charles Robert, author
Ramaja Karya, 1986
Buku Teks
edited by Peter Cumper, Tom Lewis
Edward Elgar, 2012
Buku Teks
Foster, Lois E. Elaine
Prentice-Hall, 1981
Buku Teks
Carole A. Campbell, author
Cambridge University Press, 1999
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