Sund, Robert B. <br/><br/>
Elementary science discovery lessons / 
by Robert B. Sund, Bill W. Tillery and Leslie W. Trowbridge 
 - Boston, MA :  Allyn and Bacon,  1970 
 - 3 v. :  ill. ;  22 cm. 
<br/><br/><label>LCCN: </label>70-094337 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Science--Study and teaching (Elementary)