Lagrange, Joseph Louis - A biography written with reference to his peers; includes quotations and references to his works. - http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Lagrange.html
Hamilton, Sir William Rowan (1805-1865) - Responsible for Hamilton's Principle and the classical Hamiltonian - http://www.maths.tcd.ie/pub/HistMath/People/Hamilton/
d'Alembert - Jean Le Rond d'Alembert (1717-1783) - Helped to resolve the controversy in mathematical physics over the conservation of kinetic energy by improving Newton's definition of force. A biography with references to his work and contemporaries, as well as affiliated organisations. - http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/D'Alembert.html