Data Management and Data Quality in PERCH, a Large International Case-Control Study of Severe Childhood Pneumonia. - Watson NL; Prosperi C; Driscoll AJ; Higdon MM; Park DE; Sanza M; DeLuca AN; Awori JO; Goswami D; Hammond E; Hossain L; Johnson C; et al. (Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2017)