Paolo Baldan Clara Bertolissi Horatiu Cirstea Claude Kirchner Towards a Sharing Strategy for the Graph Rewriting Calculus. 111-127 2008 204 Electr. Notes Theor. Comput. Sci. http://dx.doi.org/10.1016/j.entcs.2008.03.057 db/journals/entcs/entcs204.html#BaldanBCK08