Finding Roots of Unity Among Quotients of the Roots of an Integral Polynomial.

Kazuhiro Yokoyama Ziming Li István Nemes Finding Roots of Unity Among Quotients of the Roots of an Integral Polynomial. 85-89 1995 ISSAC http://doi.acm.org/10.1145/220346.220357 db/conf/issac/issac95.html#YokoyamaLN95