Vellekoop Jorik, Röell-Schorer Elisabeth A M, van Roosmalen Jos
Department of Obstetrics and Gynecology, Rijnland Hospital, Simon Smitweg 1, 2353 GA Leiderdorp, The Netherlands.
Acta Obstet Gynecol Scand. 2006;85(2):132-4. doi: 10.1080/00016340500405750.