TY  - BOOK
AU  - WALKER (Decker F) and HESS (Robert D)
TI  - Instructional software: principles and perspectives for design and use
SN  - 0534014593
U1  - 370.285 WALI 
PY  - 1984///
CY  - California.
PB  - Wadsworth Publishing Company.
KW  - Education
ER  -