V. Dragovic et B. Jovanovic, ON INTEGRABLE POTENTIAL PERTURBATIONS OF THE BILLIARD SYSTEM WITHIN AN ELLIPSOID, Journal of mathematical physics, 38(6), 1997, pp. 3063-3068
Generalizing Kozlov's method of integrable potential perturbations for
systems with three degrees of freedom, new integrable billiard system
s within ellipsoid in R-3 are constructed. Two countable families of t
he basic solutions in the class of the Laurent polynomials are obtaine
d. Explicit formulas are given. (C) 1997 American Institute of Physics
.