Jordan, Robert B.
Oxford University Press, 1991
Buku Teks SO
Xiao-Hong Zhang
Taylor and Francis, 2018
Artikel Jurnal
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John Wiley & Sons, 1990
Buku Teks
Henderson, Paul
Pergamon Press , 1982
Buku Teks
Mark, James E.
Prentice Hall International, 1992
Buku Teks SO