Laszl ´ o Levente T ´ oth ´, and Romanus Dyczij-Edlinger. “Hierarchical Universal Matrices for Sensitivity Analysis by Curvilinear Finite Elements”. Applied Computational Electromagnetics Society Journal (ACES), vol. 34, no. 02, Feb. 2019, pp. 206-10, https://journals.riverpublishers.com/index.php/ACES/article/view/8595.