@book{135622,
	author = {Percival, Fred. and Association for Educational and Training Technology.},
	title = {Distance learning and evaluation},
	publisher = {Kogan Page},
	year = {1981.},
	series = {Aspects of educational technology},
	address = {London},
	note = {Proceedings of the Association's fifteenth annual conference, Aberdeen, 31 March to 3 April, 1981.}
}