Butterworth-Heinemann, 1995
Buku Teks
edited by Anthony J. Marsella ... [et al.]
Springer, 2008
Buku Teks
Colorado Westview Press. , 1989
Buku Teks
Herrick, Christopher, author
Longman, 2003
Buku Teks
Wickramasinghe, Nilmini, editor
Springer, 2012
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