Forns J, Vegas O, Julvez J, Garcia-Esteban R, Rivera M, Lertxundi N, Guxens M, Fano E, Ferrer M, Grellier J, Ibarluzea J, Sunyer J. Association between child cortisol levels in saliva and neuropsychological development during the second year of life. Stress Health. 2014 Apr;30(2):142-8. doi: 10.1002/smi.2504
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.