Kettell, Brian, author
John Wiley & Sons, 2011
Buku Teks
Toman, K.
World Health Organization, 1979
Buku Teks
Hollins, Carole, author
Blackwell Munksgaard, 2006
Buku Teks
Boyd, William E., author
Prentice-Hall, 1955
Buku Teks
Leal, A.L.
Longman, 1978
Buku Teks