World Health Organization, [Date of publication not identified]
Buku Teks SO
Coughlan, Robert
Time Incorporated, 1962
Buku Teks
Eddleston, Michael
New York Oxford Univ. Press 2002,
Buku Referensi
Manson-Bahr, P.E.C.
Bailliere Tindall , 1982
Buku Teks SO
edited by Jeremy Farrar ... [and others]
Elsevier, 2014
Buku Teks SO