McConnell, Charles R.
Jones & Bartlett Learning, 2014
Buku Teks
Gray, Ivan
Learning matters Ltd., 2010
Buku Teks
Mc Connell, Charles R.
Aspen Publishing, 1982
Buku Teks
Umiker, William
Aspen Publishing, 1988
Buku Teks
United Health Foundation
BMJ Publishing Group, 2000
Buku Teks SO