[1] Department of Computer Science, Manchester, M13 9PL, Oxford Road
[2] Software Department, GEC Computers Ltd, Borehamwood, Hertfordshire, Elstree Way
[3] Department of Computer Science, University of York, Heslington, Yorkshire
[4] European Software Engineering, Digital Equipment Company Ltd, Butts Centre, Reading, RG1 7QN, Fountain House
[5] Computing Science Department, University of Glasgow, Glasgow
[6] International Data Engineering Centre, ITT Business Systems and Communications Group, Potters Bar, Hertfordshire, EN6 5DN, Latimer House
[7] Hull College of Higher Education, Hull, HU6 7LJ, Inglemire Avenue
[8] Computer Studies Group, The University, Southampton
[9] Computing Science Department, University of Glasgow, Glasgow
[10] Department of Computer Science, Queen's University, Belfast
[11] Department of Industry, National Physical Laboratory, Teddington, Middlesex