Baruss, Imants, author
Purdue Univ.Press , 1996
Buku Teks SO
Barrow, John D., author
Oxford University Press , 1998
Buku Teks SO
Hunter, Lynette
Routledge, 1999
Buku Teks SO
Wilber, Ken, author
Shambhala, 1996
Buku Teks
Simen Andersen Øyen, editor
[, Wageningen Academic], 2012
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