Bochinski, Julianne Blair, author
John Wiley & Sons, 1996
Buku Referensi
Heiserman, David L., author
Prentice-Hall, 1981
Buku Referensi
TAB Books, 1979
Buku Teks SO
Splinter, John P., author
Zondervan Publishing House, 1992
Buku Referensi
Brenner, Gary, author
Prentice-Hall, 1990
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