Johannes CB, Araujo AB, Feldman HA, Derby CA, Kleinman KP, McKinlay JB. Incidence of erectile dysfunction in men 40 to 69 years old: longitudinal results from the Massachusetts Male Aging Study. J Urol. 2000 Feb 1;163(2):460-3.
Backhouse ME, Gnanasakthy A, Schulman KA, Akehurst R, Glick H. The development of standard economic datasets for use in the economic evaluation of medicines. Drug Inf J. 2000;34(4):1273-91.