1. Askey, R., Gasper, G.: Jacobi polynomial expansions of Jacobi polynomials with non-negative coefficients. Proc. Camb. Phil. Soc. 70, 243–255 (1971)
2. Bakry, D., Gentil, I., Ledoux, M.: Analysis and geometry of Markov diffusion operators. Grundlehren der Mathematischen Wissenschaften [Fundamental Principles of Mathematical Sciences], 348. Springer, Cham, 2014. xx+552 pp. ISBN: 978-3-319-00226-2; 978-3-319-00227-9
3. Castell, W., Filbir, F., Xu, Y.: Cesro means of Jacobi expansions on the parabolic biangle. J. Approx. Theory 159(2), 167–179 (2009)
4. Cowling, M., Meda, S., Pasquale, R.: Riesz potentials and amalgams. Ann. Inst. Fourier (Grenoble) 49(4), 1345–1367 (1999)
5. Erdélyi, A., Oberhettinger, F., Tricomi, F.G.: Higher Transcendental Functions, vol. II. MaGraw-Hill, New-York (1953)