Bitzer, J., Banal-Silao, M. J., Ahrendt, H., Restrepo, J., Hardtke, M., Wissinger-Graefenhahn, U., & Trummer, D. (2015). Hormone withdrawal-associated symptoms with ethinylestradiol 20 μg/drospirenone 3 mg (24/4 regimen) versus ethinylestradiol 20 μg/desogestrel 150 μg (21/7 regimen). Int J Womens Health.

Bitzer, Johannes, Maria Jesusa Banal-Silao, Hans-Joachim Ahrendt, Jaime Restrepo, Marion Hardtke, Ulrike Wissinger-Graefenhahn, i Dietmar Trummer. "Hormone Withdrawal-associated Symptoms With Ethinylestradiol 20 μg/drospirenone 3 Mg (24/4 Regimen) Versus Ethinylestradiol 20 μg/desogestrel 150 μg (21/7 Regimen)." Int J Womens Health 2015.

Bitzer, Johannes, et al. "Hormone Withdrawal-associated Symptoms With Ethinylestradiol 20 μg/drospirenone 3 Mg (24/4 Regimen) Versus Ethinylestradiol 20 μg/desogestrel 150 μg (21/7 Regimen)." Int J Womens Health 2015.