Martin Gogolla Fabian Büttner Mark Richters USE: A UML-based specification environment for validating UML and OCL. 27-34 2007 69 Sci. Comput. Program. 1-3 http://dx.doi.org/10.1016/j.scico.2007.01.013 db/journals/scp/scp69.html#GogollaBR07