Trask JD.
Conn Med. 1989 Nov;53(11):680.
PMID: 2695286

Sepples SB.
Nursingconnections. 1992;5(3):31-8.
PMID: 1480232

KUKOWKA A.
Z Arztl Fortbild (Jena). 1953 Jun 01;47(11):406-10.
PMID: 13090935

Lycke E.
Lakartidningen. 2004 Feb 19;101(8):715.
PMID: 15024951

Burke DS.
Clin Trials. 2004 Feb;1(1):3-5. doi: 10.1191/1740774504cn013ed.
PMID: 16281456

Frost WH.
Am J Public Health (N Y). 1913 Mar;3(3):216-21. doi: 10.2105/ajph.3.3.216.
PMID: 18008809

Bedson SP.
Proc R Soc Med. 1943 Dec;37(2):41-4.
PMID: 19992749