1. P. L. Chebyshev, Collected Works [in Russian], Izd. Akad. Nauk SSSR, Moscow (1947?1951), Vol. 2, pp. 236?238, 314?334; Vol. 3, pp. 66?87.
2. E. A. Volkov, Numerical Methods [in Russian], Nauka, Moscow (1987).
3. I. I. Sharapudinov, ?On the best approximation and polynomials of the least quadratic deviation,? Anal. Math.,9, 223?234 (1983).
4. I. I. Sharapudinov, ?Interpolation of functions by Fourier sums of two-index Chebyshev polynomials,? Candidate's Dissertation, MIEM, Moscow (1977).
5. I. I. Sharapudinov, ?Approximation of functions by Fourier sums of orthogonal Chebyshev polynomials in a discrete variable,? Rept. No. 3137, Dep. in VINITI (1980).