Blough, O. Glenn Elementary school science and how to teach it / Glenn O. Blough and Julius Schwarts - 4th ed. - New York : Holt, Rinehart and Winston, 1951 - 810 p. : ill, photo ; 24 cm. Includes index ISBN: 030698901 : USD 10.95 Subjects--Topical Terms: Science--Study and teaching (Elementary) Dewey Class. No.: 372.3