@incollection(hidden,
title = "Hiding and Behaviour: an Institutional Approach",
author = "Rod Burstall and R\u{a}zvan Diaconescu",
booktitle = "A Classical Mind: Essays in Honour of C.A.R.~Hoare",
editor = "A. William Roscoe",
publisher = "Prentice-Hall",
pages = "75--92",
year = 1994)