Bester, Johannes, and Deon Kruger. 2014. “The Use of Ultrasonic Pulse Velocity Measurements to Monitor the Effectiveness of Concrete Patch Repairs”. Suid-Afrikaans Tydskrif Vir Natuurwetenskap En Tegnologie / <i>South African Journal of Science and Technology</I&gt; 33 (1), 6 bladsye. https://doi.org/10.4102/satnt.v33i1.788.