Sources used:

The Metaphysical Foundations of Modern Science, E.A. Burtt, 2003: Dover Publications, Inc., Mineola, New York

http://www.maths.uwa.edu/au/~ schultz/3M3.L20Newton.html

http://www/scidiv.bcc.ctc.edu/Math/Newton.html

http://www.comp.nus.edu/sg/~liuzhich/Calculus/Newton/influences.htm

http://tutorial.math.lamar.edu/AllBrowsers/2413/NewtonsMethod.asp

http://www2.spsu.edu/math/edwards/2253/newton.htm

http://www2.spsu.edu/math/edwards/2253/leibniz.htm