The average length of a trajectory in a certain billiard in a flat two-torus. Boca, F. P., Gologan, R. N., Zaharescu, A. (2003) The New York Journal of Mathematics [electronic only]
The Haros-Farey sequence at two hundred years. A survey. Cobeli, Cristian, Zaharescu, Alexandru (2003) Acta Universitatis Apulensis. Mathematics - Informatics
The jumping champions of the Farey series Cristian Cobeli, Kevin Ford, Alexandru Zaharescu (2003) Acta Arithmetica
The relative size of consecutive odd denominators in Farey series. Cobeli, Cristian, Iordache, Adrian, Zaharescu, Alexandru (2003) Integers