Some problems of diophantine approximation - Part II. The trigonometrical series associated with the elliptic ϑ-functions

Hardy, G. H., & Littlewood, J. E. (1914). Some problems of diophantine approximation - Part II. The trigonometrical series associated with the elliptic ϑ-functions. Acta Mathematica, 37(1), 193–239. https://doi.org/10.1007/BF02401834