How Long Is a Normal Labor? Contemporary Patterns of Labor and Birth in a Low-Risk Sample of 1,612 Women from Four Nordic Countries Hildingsson, Ingegerd, Blix, Ellen, Hegaard, Hanne Kristine, Huitfeldt, Anette, Ingversen, Karen, Olafsdottir, Olof Asta, Lindgren, Helena (2015-10-15)