Why there is an inverse primary-care law in Africa - Shabir Moosa; Silvia Wojczewski; Kathryn Hoffmann; Annelien Poppe; Oathokwa Nkomazana; Wim Peersman; Merlin Willcox; Manfred Maier; Anselme Derese; David Mant (The Lancet Global Health, 2013)