TY  - BOOK
AU  - Davis, Robert H., Alexander, Lawrence T. and Yelon, Stephen L.
TI  - Learning system design: : an approach to the improvement of instruction
SN  - 0070743347
U1  - 370.1523 
PY  - 1974///
CY  - New Delhi
PB  - ; Mcgraw-Hill Book
KW  - Education
KW  - Learning
ER  -