TY - BOOK ID - 135926552 TI - New developments in research in relation to distance education materials AU - Valcke, M. AU - Lockwood, F. PY - 1993 SN - 9035812158 PB - Heerlen Open university of the Netherlands. Centre for educational technology and innovation DB - UniCat UR - https://www.unicat.be/uniCat?func=search&query=sysid:135926552 AB - ER -