Nath, Y., P.C. Dumir, and M.L. Gandhi. 1983. “Choice of Collocation Points for Axisymmetric Nonlinear Two-Point Boundary Value Problems In Statics Of Shallow Spherical Shells”. Engineering Transactions 31 (3): 331-40. https://et3.ippt.pan.pl/index.php/et/article/view/1945.