Mansbach, Richard W., author
Houghton Miffiln, 2000
Buku Teks
Efik S., author
Elex Media Komputindo, 2018
Buku Teks
Gardner, Martin
W.H. Freeman and Company, 1982
Buku Teks
Stokes, Susan Carol, author
Cambridge University Press, 2014
eBooks
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2009
UI - Tesis (Open)