Easterly, William Russell
The white man's burden : why the West?s efforts to aid the rest have done so much ill and so little good
The Penguin Press, 2006
 Buku Teks
Cheskin, Louis
Why people by : motivation research and its successful application
Liveright, 1959
 Buku Teks
Richards, Larry E.
Business statistics : why and when
McGraw-Hill , 1983
 Buku Teks
Why don't families have more babies?
 Artikel Jurnal
Successful small business management
by Curtis E. Tate Jr. ... [and others]
Business Publication, 1982
 Buku Teks