Natalia López Manuel Núñez Ismael Rodríguez Specification, testing and implementation relations for symbolic-probabilistic systems. 228-248 2006 353 Theor. Comput. Sci. 1-3 http://dx.doi.org/10.1016/j.tcs.2005.10.047 db/journals/tcs/tcs353.html#LopezNR06