@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)