Mobile health (mHealth) approaches and lessons for increased performance and retention of community health workers in low-and middle-income countries: a review - Källander, K; Tibenderana, JK; Akpogheneta, OJ; Strachan, DL; Hill, Z; ten Asbroek, AH; Conteh, L; Kirkwood, BR; Meek, SR (Journal of medical Internet research, 2013)