Pienaar, W. “Estimation of Increased Regional Income That Emanates from Economically Justified Road Construction Projects”. Suid-Afrikaans Tydskrif Vir Natuurwetenskap En Tegnologie / <i>South African Journal of Science and Technology</I&gt;, Vol. 24, no. 4, Sept. 2005, pp. 108-17, doi:10.4102/satnt.v24i4.179.