https://unesdoc.unesco.org/in/rest/Thumb/image?id=p%3A%3Ausmarcdef_0000124208&author=Perraton%2C+Hilary&title=Teacher+education+through+distance+learning%3A+technology%2C+curriculum%2C+cost%2C+evaluation%3B+summary+of+case+studies%2C+Brazil%2C+Burkina+Faso%2C+Chile%2C+China%2C+India%2C+Mongolia%2C+Nigeria%2C+South+Africa+%28two+studies%29%2C+United+Kingdom&year=2001&TypeOfDocument=UnescoPhysicalDocument&mat=PGD&ct=true&size=512&isPhysical=1