Grundy, F., author
World Health Organization , 1973
Buku Teks
edited by Charlie Brooker and Julie Repper
Balliere Tindall, 1998
Buku Teks
Nathe, Christine Nielsen., author
Pearson Education , 2011
Buku Teks
editor, Dominique F. Charron
International Development Research Center, 2012
eBooks
Bomar, Perri J., author
Saunders , 2004
Buku Teks