 Nova methodus pro maximis et minimis by Gottfried Wilhelm Leibniz

Acta Eruditorum, pp. 467–473. The Mathematical Association of America reproduces the original pages. Cited for the published differential-calculus rules, not for a modern reconstruction of their foundations.

Online source: old.maa.org/press/periodicals/convergence/mathematical-treasure-leibnizs-papers-on-calculus-differential-calculus