CASEY, A E Incidence of subclinical poliomyelitis in an urban area according to age groups. [electronic resource] - American journal of public health and the nation's health Oct 1950 - 1241-50 p. digital Publication Type: Journal Article ISSN: 0002-9572 Standard No.: 10.2105/ajph.40.10.1241 doi Subjects--Topical Terms: HumansIncidencePoliomyelitis