TY  - BOOK
AU  - Hartley, J.,
TI  - Strategies for programmed instruction: an educational technology 
SN  - 0408702524
U1  - 371.3944 
PY  - 1972///
CY  - London
PB  - Butterworths
KW  - Educational technology
KW  - Programmed instruction
N1  - Bibliography: p. 209-224
ER  -