Williams, Tennessee
Penguin Books , 1964
Buku Teks SO
Wawan Christiawan
Fakultas Ilmu Pengetahuan Budaya Universitas Indonesia, 2002
UI - Tesis Membership
F. Gary Cunningham, Norman F. Gant, Kenneth J. Leveno, Larry C. Gilstrap III, John C. Hauth, Katharine D. Wenstrom, editor
McGraw-Hill, 2001
Buku Referensi
Pritchard, Jack A.
Airlangga University , 1991
Buku Teks SO
editors, Kenneth Kaushansky, Marshall A. Lichtman, Josef T. Prchal, Marcel Levi, Oliver W. Press, Linda J. Burns, Michael A. Caligiuri.
McGraw-Hill Education, 2016
Buku Teks SO