https://amref.org/research-papers/patient-retention-in-antiretroviral-therapy-programs-up-to-three-years-on-treatment-in-sub-saharan-africa-2007-2009-systematic-review-patient-retention-in-antiretroviral-therapy-programs-tropical-m/
Patient retention in antiretroviral therapy programs up to three years on treatment in sub-Saharan Africa, 2007-2009: systematic review: Patient retention in antiretroviral therapy programs Tropical Medicine & International Health 2010