Browning, Carl H.
Oxford University Press, 1937
Buku Referensi
Muir, Robert
Henry Frowde, Hodder & Stoughton, 1921
Buku Teks
Toennies, Klaus D.
Springer, 2012
eBooks
World Health Organization, 1991
Buku Teks
Chatton, Milton
University Medical Publishers, 1949
Buku Referensi