Czapp, S. “Elimination of the Negative Effect of Earth Fault Current Higher Frequency on Tripping of Residual Current Devices”. Elektronika ir Elektrotechnika 91, no. 3 (March 19, 2009): 85–88. Accessed February 7, 2026. https://eejournal.ktu.lt/index.php/elt/article/view/10610.