1. On the Application of Perturbation Methods to the Beam-beam Interaction;Bountis,1980
2. R.H.G. Helleman, in the same volume as Ref. [1].
3. Synchronized periodic orbits in beam-beam interaction models in one and two spatial dimensions;Bountis;Part. Accel.,1987
4. Method of stochastic normal forms;Namachchivaya;Int. J. Non-Linear Mech.,1991