Brodtkorb T, Kogler GF, Arndt A. The influence of metatarsal support height and longitudinal axis position on plantar foot loading. Clin Biomech (Bristol, Avon). 2008;23(5):640-7.
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.