1. Maternal characteristics and twin gestation outcomes over 10 years: impact of conception methods 
Christian Bamberg, M.D., Christina Fotopoulou, M.D., Ph.D., Philipp Neissner, M.D., Torsten Slowinski, M.D., Joachim W. Dudenhausen, M.D., Ph.D., Hans Proquitte, Ph.D., Christoph Bührer, M.D., Ph.D., Wolfgang Henrich, M.D., Ph.D. 
Fertility and Sterility 
Volume 98, Issue 1, Pages e1 (July 2012)
DOI: /j.fertnstert
Copyright © 2012 American Society for Reproductive Medicine Terms and Conditions

2. Figure 1
Mean maternal age during the study period by mode of conception.
Fertility and Sterility  , e1DOI: ( /j.fertnstert )
Copyright © 2012 American Society for Reproductive Medicine Terms and Conditions

3. Figure 2
Number of annual twin deliveries between 1998 and 2008 by mode of conception.
Fertility and Sterility  , e1DOI: ( /j.fertnstert )
Copyright © 2012 American Society for Reproductive Medicine Terms and Conditions