Paul Randolph E.
Little, Brown & Co., 1954
Buku Teks
Pinto, Dale
IBFD, 2002
Buku Teks
Fox, James R., author
Oceana Publications, Inc, 1992
Buku Teks
Laiden : Brill Academic Publishers
Majalah, Jurnal, Buletin
Tade Matthias Spranger
Springer, 2012
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