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2. On Singular Integrals with Complex Homogeneity;Ash,1972
3. P. Ash, J. M. Ash, and R. D. Ogden, A characterization of isometries with applications, available from the authors upon request.
4. On certain singular integrals;Muckenhoupt;Pacific J. Math.,1960
5. Functional Analysis;Riesz,1955