1. Akhiezer, N.I.: Orthogonal polynomials on several intervals, Dokl. Akad. Nauk SSSR 134 (1960) 9-12 (in Russian). English transi.: Soviet Math. Dokl (1960) 1 989–992.
2. Al-Salam, W., Allaway, W. and Askey, R.: Sieved ultraspherical polynomials, Trans. Amer. Math. Soc. 284 (1984) 39–55.
3. Aptekarev, A.I.: Asymptotic properties of polynomials orthogonal on a system of contours and periodic motions of Toda lattice, Math. Sb. 125(167) (1984) 231–258 (in Russian). English transi. Math. USSR-Sb. 53 (1986) 233-260.
4. Barkov, G.I.: On some systems of polynomials orthogonal on two symmetric intervals, Izvestia Vyssch. Uchebn. Zaved., Mathem. (1960) no. 4, 3–16 (in Russian).
5. Berezanskyi, Y.M. and Kalyuzhnyi, A.A.: Harmonic Analysis in Hypercomplex Systems, Naukova Dumka, Kiev, 1995 (in Russian).