1. On the vibrations of a particle in the plane;Yang;Int. J. non-linear Mech,1967
2. On forced vibrations of a particle in the plane;Yang;Int. J. non-linear Mech,1968
3. Richard, H. Rand, and Shoe,i-Fu Tseng, On the stability of a differential equation with application to the vibrations of a particle in the plane. To be published in J. appl. Mech..
4. Nonlinear Vibrations;Stoker,1950