M. Vozda, B. Hrvolova, J. Krohova, M. Smondrk, and M. Penhaker, “Computer-Based Vectorcardiograph for Research Purposes”, ELEKTRON ELEKTROTECH, vol. 19, no. 9, pp. 61–64, Nov. 2013, doi: 10.5755/j01.eee.19.9.5650.