Jarzębowski, Andrzej, and Jan Maciejewski. “Some Remarks on the Applicability of Rectangular Elements to Plane Strain Boundary Value Problems”. Computer Assisted Methods in Engineering and Science, vol. 5, no. 3, May 2023, pp. 299-0, https://cames3.ippt.pan.pl/index.php/cames/article/view/1346.