This text is missing some spaces, please add them: TwoofhismonographsThemethodoftrigonometricsumsinthetheoryofnumbers,andSpecialvariantsofthemethodoftrigonometricsumsarealsointhebook.
Two of his monographsThe method of trigonometric sums in the theory of numbers, and Special variants of the method of trigonometric sums are also in the book.