Bibby, Colin J.
Academic Press, 1993
Buku Teks
Schwab, Glenn Orville, 1919-, author
John Wiley & Sons, 1993
Buku Teks
Schall, Lawrence D., author
McGraw-Hill 1982, 1982
Buku Teks
Westview Press, 1987
Buku Teks
Kruijtbosch, D.J.
L. J. C. Boucher, 1941
Buku Teks