Dine JL, Schneider MK, Stewart BR, Armer JM. Learning from traditional healers in South Africa. J Lymphoedema. 2009;4(2):10-6.
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.