Pollock, George, author
Springer, 2012
eBooks
Webber, Roger, author
Cab International, 1996
Buku Teks
Hawker, Jeremy, author
Wiley-Blackwell, 2012
Buku Teks
Bennett, Claire L., author
John Wiley & Sons, 1982
Buku Teks
American Public Health Association, 2015
Buku Teks