An assessment of primary health care costs and resource requirements in Kaduna and Kano, Nigeria oleh Yewande Ogundeji, Hamza Abubakar, Uche Ezeh, Tijjani Hussaini, Nelson Kamau, Eliza Love, Rodrigo Muñoz, Paul Ongboche, Marjorie Opuni, Damian G. Walker, Colin Gilmartin