<A HREF="http://hyperion.advanced.org/12170/history/Lorenz.html">

<A HREF="http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Poincare.html">
http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Hopf.html
http://www.cs.brown.edu/research/ai/dynamics/tutorial/home.html  