1. G. H. Hardy and J. E. Littlewood, “Some problems of Diophantine approximation. II: The trigonometrical series associated with the elliptic v-functions,” Acta Math. 37, 193–239 (1914).
2. I. M. Vinogradov, “On the mean value of the number of classes of proper primitive forms of negative discriminant,” Soobshch. Kharkov. Mat. Obshch., Ser. 2, 16 (1–2), 10–38 (1918).
3. J. G. van der Corput, “Verschärfung der Abschätzung beim Teilerproblem,” Math. Ann. 87 (1–2), 39–65 (1922).
4. I. M. Vinogradov, “On the distribution of fractional parts of values of functions of two variables,” Izv. Leningr. Politekhn. Inst. 30, 31–52 (1927).
5. E. C. Titchmarsh, “On van der Corput’s method and zeta function of Riemann. I, II,” Q. J. Math. 2, 161–173, 313–320 (1931).