1. J. Cassaigne, P. Hubert and S. Troubetzkoy, Complexity and growth for polygonal billiards, Ann. Inst. Fourier 52 (2002), 835–847.
2. E. Gutkin and M. Rams, Growth rates for geometric complexities and counting functions in polygonal billiards, Ergodic Theory Dynam. Systems 29 (2009), 1163–1183.
3. E. Gutkin and S. Tabachnikov, Complexity of piecewise convex transformations in two dimensions, with applications to polygonal billiards on surfaces of constant curvature, Mosc. Math. J. 6 (2006), 701–772.
4. E. Gutkin and S. Troubetzkoy, Directional flows and strong recurrence for polygonal billiards, in International Conference on Dynamical Systems (Montevideo, 1995), Longman, Harlow, 1996, pp. 21–45.
5. V. Kaloshin and I. Rodnianski, Diophantine properties of elements of SO(3), Geom. Funct. Anal. 11 (2001), 953–970.