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[2] W. E. Boyce and R. C. DiPrima. Elementary Differential Equations. Wiley, New York, 10th edition, 2012.
[3] J. L. R. d'Alembert. Extract de différentes lettres de M. d'Alembert à M. De La Grange écrites pendant les années 1764 & 1765. Misc. Taurinensia, 3:381-396, 1766. Available online via Google Books.
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[8] Thomas L. Hankins. Jean d'Alembert: Science and the Enlightenment. Gordon and Breach Science, New York, 1970.
[9] E. L. Ince. Ordinary Differential Equations. Dover Publications, New York, 1944.
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[13] J.J. O’Connor and E.F. Robertson, Jean Le Rond d'Alembert, MacTutor History of Mathematics Archive. October 1998.
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[15] D. Zill. A First Course in Differential Equations: The Classic Fifth Edition. Cengage, Pacific Grove CA, 2000.
[16] D. Zwillinger. Handbook of Differential Equations. Academic Press, Waltham Mass., 3rd edition, 1997, reprinted 2007. Available online in pdf format.