Year	Where
	1940 - 1958	Bolton
	1947 - 1958	Bolton School
	1958 - 1964	Sheffield University
	1964 - 1966	National Research Council Ottawa
	1966 - 1967	Bell Telephone Laboratories NJ
	1967 -	University of Sussex
	1990 - 1995	UCLA - Visiting Professor
	1996 -	UCSB - Visiting Professor