TY  - BOOK
AU  - Gerlach, Vernon S.; Ely, Donald P. &  Melnick, Rob
TI  - Teaching & media : a systematic approach
SN  - 0-13-891358-7
U1  - 371.33 Ger/Ely 
PY  - 1980///
CY  - Prentice Hall, New Jersey
ER  -