J. V. Tucker Jeffery I. Zucker Computable total functions on metric algebras, universal algebraic specifications and dynamical systems. 71-108 2005 62 J. Log. Algebr. Program. 1 http://dx.doi.org/10.1016/j.jlap.2003.10.001 db/journals/jlp/jlp62.html#TuckerZ05