(Kulier 2007) Kulier R, O'Brien P, Helmerhorst FM, Usher-Patel M, d'Arcangues C. Copper containing, framed intra-uterine
(Klipping 2008) Klipping C, Duijkers I, Trummer D, Marr J. Suppression of ovarian activity with a drospirenon-containing oral contraceptive in a
