Teacher's guide for Small things :  [a study unit] / 
Elementary Science Study. 
 - St. Louis :  Webster Division, McGraw-Hill,  c1967. 
<br/><br/> "Foreword" signed by Charles Walcott. 
<br/><br/>Bibliography: p. 144-146. 
<br/><br/><label>ISBN: </label>007019369X 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Microscope and microscopy -- Study and teaching (Elementary)--Microscope and microscopy -- Study and teaching (Elementary)