1. 1. Paul J. Cohen, Topics in the theory of uniqueness of trigonometrical series, Thesis, University of Chicago, Chicago, III., 1958.
2. Trigonometrische Doppelreihen;Geiringer, Hilda;Monatsh. Math. Phys.,1918
3. On the convergence of Fourier series;Hunt, Richard A.,1968
4. 4. B. Jessen, J. Marcinkiewicz and A. Zygmund, Note on the differentiability of multiple integrals, Fund. Math. 25 (1935), 217-234.
5. Uniqueness of multiple trigonometric series;Shapiro, Victor L.;Ann. of Math. (2),1957