Liess, H. D., and A. Ilgevičius. “Analytical Versus Numerical Calculations of Physical Problems. The Benefits of Its Combination”. Mathematical Modelling and Analysis 8, no. 4 (December 31, 2003): 291-302. Accessed August 17, 2022. https://journals.vilniustech.lt/index.php/MMA/article/view/9785.