Adeyemi, Adewale, Peter Molnar, Johan Boman, and Janine Wichmann. “Source Apportionment of Fine Atmospheric Particles Using Positive Matrix Factorization in Pretoria, South Africa”. Clean Air Journal 32, no. 1 (June 24, 2022). Accessed August 11, 2022. https://cleanairjournal.org.za/article/view/13931.