Oshaug, A.
WHO, 1993
Buku Referensi
Guilbert, J.J.
World Health Organization, 1998
Buku Referensi
McGraw-Hill, 2003
Buku Teks
Carliner, Saul, author
American Society for Training & Development Press, 2002
eBooks
Andersen, Elaine, author
DocMatrix, 1999
Buku Teks