1. Berg, Christian, written communication, (December, 1981).
2. Chihara, T.S. Introduction to Orthogonal Polynomials (Mathematics and Its Applications Ser.), Gordon, (1978).
3. Favard, J., Sur les polynomes de Tchebicheff, C.R. Acad. Sci. Paris 200 (1935), 2052–2053.
4. Gautschi, Walter, Construction of Gauss-Christoffel quadrature formulas, Math. Comp. 22 (1968), 251–270.
5. Gautschi, Water, A survey of Gauss-Christoffel quadrature formulae, Christoffel Memorial Volume (P.L. Butzer and F. Feher, eds.), Birkhäuser Verlag (1981), 72–147.