Implementation of Certified Endometriosis Centers: 5-Year Experience in German-Speaking Europe. - Ebert, A.D.; Ulrich, U.; Keckstein, J.; Müller, M.; Schindler, A.E.; Sillem, M.; Tinneberg, H.-R.; De Wilde, R.L.; Schweppe, K.-W. (Gynecologic & Obstetric Investigation, 2013)