1. Positive zonal functions on spheres;Bochner, S.;Proc. Nat. Acad. Sci. U.S.A.,1954
2. A. Erdelyi et al., Higher transcendental functions, New York, 1953.
3. The decomposition of Walsh and Fourier series;Hirschman, I. I.;Mem. Amer. Math. Soc.,1955
4. Weighted quadratic norms and Legendre polynomials;Hirschman, I. I., Jr.;Canadian J. Math.,1955
5. A note on orthogonal systems;Hirschman, I. I., Jr.;Pacific J. Math.,1956