1. Ebenfelt, P., Khavinson, D., Shapiro, H.S.: An inverse problem for the double layer potential. Comput. Methods Funct. Theory 1(2), 387–401 (2001)
2. Shapiro, H.S.: The Schwarz Function and Its Generalization to Higher Dimensions. University of Arkansas Lecture Notes in the Mathematical Sciences, vol. 9, p. 108. John Wiley & Sons, Inc., A Wiley-Interscience Publication, New York (1992)
3. Shapiro, H.S.: Clear thinking will never be out of date. Int. J. Math. Educ. Sci. Technol. 16(2), 301–308 (1985)
4. Shapiro, H.S.: Topics in Approximation Theory. Lecture Notes in Mathematics, vol. 187. Springer, Berlin-New York (1971)
5. Shapiro, H.S.: Smoothing and Approximation of Functions. Van Nostrand Reinhold Mathematical Studies, p. 136. Van Nostrand Reinhold Co., New York-Toronto, Ont.-London (1969). Revised and expanded edition of mimiographed notes (Matscience Report No. 55)