Hartmut Ehrig Ingo Claßen Paul Boehm Werner Fey Martin Korff Michael Löwe Algebraic Concepts for Software Development in ACT ONE, ACT TWO and LOTOS (eingeladener Vortrag). 201-224 1989 conf/softent/1989 Software-Entwicklung db/conf/softent/softent1989.html#EhrigCBFKL89