1. Department of Epidemiology , Erasmus MC , University Medical Center Rotterdam , Dr. Molewaterplein 50 , Office NA29-14, PO Box 2040, 3000 CA Rotterdam , the Netherlands
2. Department of Public Health , Uludag University School of Medicine , Bursa , Turkey
3. Leiden University College , The Hague , the Netherlands
4. Medical Library, Erasmus MC , University Medical Center Rotterdam , the Netherlands
5. Department of Gynecology , Utrecht Medical Center , Utrecht , the Netherlands
6. Department of Epidemiology , Harvard T.H. Chan School of Public Health , Boston , MA , USA