TY  - BOOK
AU  - Simonson,Michael R.
TI  - Teaching and learning at a distance: foundations of distance education 
SN  - 9780135137765
AV  - LC5800 T435 2009
U1  - 371.35 22
PY  - 2009///
CY  - Boston
PB  - Allyn and Bacon
KW  - Educación a distancia
ER  -