M. A. Sarhan, S. SHIHAB, and M. RASHEED, “A Novel Spectral Modified Pell Polynomials for Solving Singular Differential Equations”, Al-Mustansiriyah Journal of Science, vol. 32, no. 1, pp. 18–24, Feb. 2021, doi: 10.23851/mjs.v32i1.930.