The key of the mathematicks new forged and filed : together with a treatise of the resolution of all kinde of affected æquations in numbers : vvith the rule of compound usury, and demonstration of the rule of false position : and a most easie art of delineating all manner of plaine sun-dyalls / - Oughtred, William, (Printed by Tho. Harper for Rich. Whitaker ...,, 1647)