TY  - BOOK
AU  - Verduin, John R.
AU  - Clark, Thomas A.,
TI  - Distance education: the foundations of effective practice 
SN  - 155542306X
AV  - LC5800 V47
PY  - 1991///
CY  - San Francisco, California
PB  - Jossey-Bass
KW  - Educación a Distancia
ER  -