Stehle, T., Eisseler, R., Drewle, K., Weiland, S., & Twiefel, J. (2015). Investigation of process forces of ultrasonically assisted scratch tests. International Conference on Stone and Concrete Machining (ICSCM), 3, 137–145. https://doi.org/10.13154/icscm.3.2015.137-145