Não informado. (1921). American Journal of Hygiene. John Hopkins University, School of Hygiene and Public Health.
Chicago-referens (17:e uppl.)Não informado. American Journal of Hygiene. Baltimore, Md: John Hopkins University, School of Hygiene and Public Health, 1921.
MLA-referens (8:e uppl.)Não informado. American Journal of Hygiene. John Hopkins University, School of Hygiene and Public Health, 1921.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.