Brenner, Robert L., author
International Human Resources Development Corp, 1984
Buku Teks
Fink, Johannes Karl, author
Elsevier, 2015
Buku Teks
Levorsen, A.I.
San Fransisco: W.H. Freeman, 1967
Buku Teks
Tver, David F.
Van Nostrand Reinhold Co., 1980
Buku Referensi
Uren, Lester C.
New York: McGraw-Hill, 1950
Buku Teks