Cost and impact of policies to remove and reduce fees for obstetric care in Benin, Burkina Faso, Mali and Morocco. - Witter, S.; Boukhalfa, C.; Cresswell, J. A.; Daou, Z.; Filippi, V.; Ganaba, R.; Goufodji, S.; Lange, I. L.; Marchal, B.; Richard, F. (International Journal for Equity in Health, 2016)