A Deterministic Algorithm for Solving n = fu 2 + gυ 2 in Coprime Integers u and υ
Kenneth Hardy, Joseph B. Muskat, Kenneth S. Williams · Mathematics of Computation · 1990
Kenneth Hardy, Joseph B. Muskat, Kenneth S. Williams, A Deterministic Algorithm for Solving $n = fu^2 + g\upsilon^2$ in Coprime Integers $u$ and $\upsilon$, Mathematics of Computation, Vol. 55, No. 191 (Jul., 1990), pp. 327-343