S. Hlongwane, C. Ngongoni, and S. S. (Saartjie) Grobbelaar, “A PATIENT-CENTRIC SIX-SIGMA DECISION SUPPORT SYSTEM FRAMEWORK FOR CONTINUOUS QUALITY IMPROVEMENT IN CLINICS”, S AFR J IND ENG, vol. 30, no. 3, pp. 224–237, Nov. 2019.