Application of system thinking concepts in health system strengthening in low-income settings: a proposed conceptual framework for the evaluation of a complex health system intervention: the case of the BHOMA intervention in Zambia. - Mutale, Wilbroad; Balabanova, Dina; Chintu, Namwinga; Mwanamwenge, Margaret Tembo; Ayles, Helen (Journal of Evaluation in Clinical Practice, 2014)