Retraction Note: Improving usability and pregnancy rates of a fertility monitor by an additional mobile application: results of a retrospective efficacy study of Daysy and DaysyView app

oleh: Martin C. Koch, Johannes Lermann, Niels van de Roemer, Simone K. Renner, Stefanie Burghaus, Janina Hackl, Ralf Dittrich, Sven Kehl, Patricia G. Oppelt, Thomas Hildebrandt, Caroline C. Hack, Uwe G. Pöhls, Stefan P. Renner, Falk C. Thiel