TY  - BOOK
AU  - Weaver, Gilbert G
AU  - Bollinger, Elroy W
TI  - Visual aids: their construction and Use 
U1  - 371.355 22
PY  - 1949///
CY  - New York
PB  - D. Van Nostrand Co. INC.
KW  - Sociology
N1  - Includes bibliographical references and index
ER  -