Active perinatal care of preterm infants in the German Neonatal Network - Humberg, Alexander; Härtel, Christoph; Rausch, Tanja Katrin; Stichtenoth, Guido; Jung, Philipp; Wieg, Christian; Kribs, Angela; Wense, Axel von der; Weller, Ursula; Höhn, Thomas; Olbertz, Dirk Manfred; Felderhoff-Müser, Ursula; et al. (Archives of disease in childhood. Fetal & neonatal, 2020)