Bradley RH, National Institute of Child Health and Human Development (NICHD) Early Child Care Research Network, McLeod LD. Child care and common communicable illnesses in children aged 37 to 54 months. Arch Pediatr Adolesc. 2003 Feb;157(2):196-200. doi: 10.1001/archpedi.157.2.196
Derby CA, Araujo AB, Johannes CB, Feldman HA, McKinlay JB. Measurement of erectile dysfunction in population-based studies: the use of a single question self-assessment in the Massachusetts Male Aging Study. Int J Impot Res. 2000 Aug 1;12(4):197-204.