@book{154582,
	author = {The Open University.},
	title = {Introduction Unit1- 2:},
	publisher = {The Open Univesty,},
	year = {1992},
	series = {Technology:a second level course.},
	address = {London },
	edition = {T237 Units 1 and 2.},
	note = {Includes bibliogrphical references.}
}