Kassirsky, I.
Peace Publisher, [Date of publication not identified]
Buku Referensi
American Public Health Association, 2015
Buku Teks
Spicer, John W.
Churchill Livingstone Elsevier, 2008
Buku Teks
Wright, William F. (William Floyd)
Demos, 2013
Buku Teks
Adams, A.R.D.
Blackwell Scientific Publications, 1966
Buku Teks