Mehrotra, Chandra Mohan
Distance learning : principles for effective design, delivery, and evaluation
Sage Publications, 2001
 Buku Teks
Gerber, Philip L.
Effective english
Random House, 1959
 Buku Teks
Achua, Christopher F.
Effective leadership
South Western Cengage Learning, 2013
 Buku Teks
Cook, Marshall J. ,author
Effective coaching
McGraw-Hill, 2011
 Buku Teks
Drucker, Peter Ferdinand, 1909-2005
The effective executive
Harper & Row, 1996
 Buku Teks