[1] Spector IP, Carey MP. Incidence and prevalence of sexual dysfunctions: a critical review of the empirical literature. Arch Sex Behav 1990;19:389-408. [2] Diagnostic and statistical manual of mental disorders, fourth edition, text revision: DSM-IV-TR. Washington (DC): American Psychiatric Association; 2000. p. 554. [3] Waldinger MD, Zwinderman AH, Schweitzer DH, et al. Relevance of methodological design for the interpretation of efficacy of drug treatment of premature ejaculation: a systematic review and meta-analysis. Int J Imp Res 2004;1:1-13. [4] Patrick DP, Althof SE, Pryor JL, et al. Premature ejaculation: an observational study of men and their partners. J Sex Med 2005;2:358-67.