1. I. Schur, “Über Potenzreihen, die im Innern des Einheitskreises beschränkt sind,” J. Reine Angew. Math. 147, 205–232 (1917).
2. H.-J. Runkel, “Bounded analytic functions in the unit disk and the behaviour of certain analytic continued fractions near the singular line,” J. Reine Angew. Math. 281, 97–125 (1976).
3. W. B. Jones, O. Njåstad, and W. J. Thron, “Schur fractions, Perron–Carathéodory fractions and Szegő polynomials, a survey,” in Lecture Notes in Math., Vol. 1199: Analytic Theory of Continued Fractions. II (Springer-Verlag, Berlin, 1986), pp. 127–158.
4. V. I. Buslaev, “Schur’s criterion for formal power series,” Mat. Sb. 210 (11), 58–75 (2019) [Sb. Math. 210 (11), 1563–1580 (2019)].
5. E. B. Saff and V. Totik, Logarithmic Potentials with External Fields, in Grundlehren Math. Wiss. (Springer-Verlag, Berlin, 1997), Vol. 316.