Artikel Jurnal
Depok Pusat Penelitian Kesehatan Lembaga Penelitian UI 1991,
Buku Referensi
Clark, Rory McDowall, author
McGraw-Hill, 2012
Buku Teks
Williamson, Mark, author
Institution of Engineering and Technology, 2008
eBooks
Chaplin, Charles, author
Chivers, 1964
Buku Teks