Clarifications concerning the commentary "Published analysis of contraceptive effectiveness of Daysy and DaysyView app is fatally flawed". - Koch MC; Lermann J; van de Roemer N; Renner SK; Burghaus S; Hackl J; Dittrich R; Kehl S; Oppelt PG; Hildebrandt T; Hack CC; Pöhls UG; et al. (Reproductive health, 2019)