“Symmetric boundary integral formulations of transient heat conduction: saddle-point theorems for BE analysis and BE-FE coupling”, Arch. Mech., vol. 49, no. 2, pp. 253–283, Jan. 1997, Accessed: May 13, 2025. [Online]. Available: https://am3.ippt.pan.pl/index.php/am/article/view/v49p253