@book{15242,
	author = {Clarke, A.D.B. , Lewis, M.M.},
	title = {Learning Speech and Thought in the Mentally Retarded: Proceedings of Symposia 4 and 5 Held at the Middlesex Hospital Medical Sessions on 31st Oct1969 and 20th March 1970, Under the Auspices of the Institute for Research in the Mental Retardation, London},
	publisher = {London},
	year = {1972}
}