1. Dewan PA, Zappala SM, Duffy PG, Ransley PG (1992) An endoscopic reappraisal of the morphology of congenital obstruction of the posterior urethra. Br J Urol, in press
2. Field PL, Stephens FD (1974) Congenital urethral membranes causing urethral obstruction. J Urol 111: 250–255
3. Hendren WH (1977) Urethral valves. In: Bergsma D, Duckett JW (eds) Birth defects: urinary system malformations in children. Liss, New York, pp 75–86
4. King LR (1985) Posterior urethra. In: Kelalis PP, King LR, Belman AB (eds) Clinical pediatric urology, 2nd edn. Saunders, Philadelphia, pp 527–558
5. Parkkulainen KV (1977) Posterior urethral obstruction: valvular or diaphragmatic? Endoscopic diagnosis and treatment. In: Bergsma D, Duckett JW (eds) Birth defects: urinary system malformations in children. Liss, New York, pp 63–74