(Gallo 2008/2011) Gallo MF, Nanda K, Grimes DA et al. 20 μg versus > 20 μg estrogen combined oral contraceptives for
(Glasier 2010) Glasier AF, Cameron ST, Fine PM, et al. Ulipristal acetate versus levenorgestrel for emergency contraception: a randomised noninferiortiy trial and meta-analysis.