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.
Agha M, Gnanasakthy A. A cluster analysis of the effects of storage mites as allergens in relation to certain occupations and living conditions. Clin Allergy. 1981 Sep;11(5):499-504.