books.google.com - The book presents the theory of multiple trigonometric sums constructed by the authors. Following a unified approach, the authors obtain estimates for these sums similar to the classical I. M. Vinogradovs estimates and use them to solve several problems in analytic number theory. They investigate trigonometric...http://books.google.com/books/about/Trigonometric_Sums_in_Number_Theory_and.html?id=ajo2ehxA5VkC&q=function&utm_source=gb-gplus-shareTrigonometric Sums in Number Theory and Analysis