1. O. Veblen, A conformal wave equation, Proceedings of the National Academy of Sciences, vol. 21 (1935), p. 484.
2. P. A. M. Dirac, Wave equations in conformal space, Annals of Mathematics, (2), vol. 37 (1936), p. 429.
3. Due especially to S. Bernstein, Jackson, Lebesgue, Montel, and de la Vallée Poussin.
4. Due especially to J. Curtiss, Sewell, and Walsh.
5. The notation F (p) (z) indicates the pth derivative of F(z), if p> 0, and the function F(z) itself for p = 0. Here and below, such derivatives on the boundaries of regions of analyticity are considered in the one-dimensional sense.