White, Charles
Haynes Publishing, 1992
Buku Referensi
White, Charles
Haynes Publishing, 1992
Buku Referensi
Zenith Data Systems, 1986
Buku Teks
Grolle, Carl G.
Parker Publishing Company, 1977
Buku Referensi
Abbatt, Fred
World Health Organization, 1988
Buku Teks