Wagner, Sigrid ed. <br/><br/>
Modeling mathematical cognitive development 
edited by Sigrid, Wagner and William E. Geeslin 
 - Ohio  Eric clearing house for  Science , Mathematics & Environmental Education  1981 
 - viii,143p.: ill. ;28cm. 
 - Mathematics education information report .
<br/><br/><label>Dewey Class. No.: </label>510.7  / WAG