Reshetukha, I. V. “Generalized Sums for Characters and Their Applications to the Reciprocity Laws ”.
Ukrains’kyi Matematychnyi Zhurnal
, vol. 23, no. 2, Feb. 1971, pp. 270-6,
https://umj.imath.kiev.ua/index.php/umj/article/view/8514
.