Tosen, G.R., A.P.S. Terblanche, L. Uys, and C.R. Turner. 1992. “DESIGN AND OPERATION OF AN AMBIENT AIR POLLUTION MONITORING NETWORK IN THE VAAL TRIANGLE AIR POLLUTION HEALTH STUDY”. Clean Air Journal 8 (6):9-14. https://doi.org/10.17159/caj/1992/8/6.7129.