S. V. Vostokov, P. M. Vinnik, “The numbers of representations of elements of $GF(p)$ as sums of $l$th degrees”, Zap. Nauchn. Sem. POMI, 236 (1997), 68–72; J. Math. Sci. (New York), 95:2 (1999), 2085–2087
1995
2.
G. V. Abramov, P. M. Vinnik, “Computation of the number of representations of the elements of the ring $\mathbb Z/d\mathbb Z$ as a sum of squares”, Zap. Nauchn. Sem. POMI, 227 (1995), 5–8; J. Math. Sci. (New York), 89:2 (1998), 1079–1081