“…In a more general setting Hua-Vandiver [7] as well as Weil [18] give formulas for the number of solutions involving Jacobi sums (see also [9, Chapter 8, Theorem 5] for a comprehensive exposition and [10] for more literature). However, these formulas are hard to evaluate for large m. Explicit and simple formulas are only known for certain special cases, namely when m is small [5,13], when k is small [17,13], or when 2\s and m\(^/q + 1) ( [14,8,6] and, more general, [19]). …”