 Chen, Z. 

 Chen, Z. (Z. Chen and F. Ameur)  The learnability of unions of two rectangles in the twodimensional discretized space  1999 
 Chen, Z. (Z. Chen)  Learning unions of two rectangles in the plane with equivalence queries  1993 
 Chen, Z. (Z. Chen and W. Maass)  Online learning of rectangles  1992 
 Chen, Z. (Z. Chen and S. Homer)  The bounded injury priority method and the learnability of unions of rectangles  1996 
