A warning to the flocks against wolves in sheeps cloathing, or, A Faithful advice, from several ministers of the Gospel, in and near Boston, unto the churches of New-England, relating to the dangers that may arise from imposters pretending to be ministers [electronic resource] : with a brief history of some impostors, remarkably and seasonably detected / written by one of the ministers in Boston to assert that advice, and prevent future mischiefs.