Learning, speech and thought in the mentally retarded : proceedings of Symposia 4 and 5 held at the Middlesex Hospital Medical School on 31 October 1969 and 20 March 1970 under the auspices of the Ins. ISBN 0407249508. Published by Butterworths for the Institute for Research into Mental Retardation in 1972. Publication and catalogue information, links to buy online and reader comments.