Gander, Walter <br/><br/>
The billiard problem 

 - 825-830 
 - 1992 Vol. 23, no. 6, nov.-dec. 
 = INTERNATIONAL JOURNAL OF MATHEMATICAL EDUCATION IN SCIENCE AND TECHNOLOGY 
<br/><br/><label>Encabezamiento--Término de Indización: </label>ALGEBRA ENSEÑANZA GEOMETRIA MATEMATICA SOFTWARE EDUCATIVO