Wonderling, David
Open University Press, 2005
Buku Teks
Kobelt, Gisela
Office of Health Economics, 2002
Buku Teks
Sorkin, Alan L.
Massachusetts Lexington Books, 1984
Buku Teks
McLean, Robert A.
Delmar, 1997
Buku Teks
McLean, Robert A.
Delmar, 2003
Buku Teks