1. [1] S. Bochner. Harmonic Analysis and the Theory of Probability. University of California Press, Berkeley, 1955.
2. [2] J. Dieudonné. Treatise on Analysis, Vol. VI. Academic Press, New York, 1978.
3. [3] C. S. Herz. Analyse Harmonique à Plusieurs Variables. Publications du Séminaire de Mathématiques d'Orsay, 1965.
4. [4] E. W. Hobson. On a theorem in the differential calculus. Messenger Math. 23 (1894), 115-119.
5. [5] E. W. Hobson. The Theory of Spherical and Ellipsoidal Harmonics. Chelsea, New York, 1955.