Gilles Kahn Bernard Lang Bertrand Melese Elham Morcos Metal: A Formalism to Specify Formalisms. 151-188 1983 3 Sci. Comput. Program. 2 db/journals/scp/scp3.html#KahnLMM83 http://dx.doi.org/10.1016/0167-6423(83)90009-6