duffing系统的matlab分岔程序，对于初学者有一定的帮助。-The bifurcation matlab procedure of Duffing system, which would be helpful for beginners.

Lorenz的关于参数r的分叉和画图程序，是比较好的参考的文献。-Lorenz on the bifurcation parameter r and the Paint program, is a better reference literature.