@article {2002, title = {Admissible Riemann solvers for genuinely nonlinear P-systems of mixed type}, journal = {J. Differ. Equations, 2002, 180, 395}, number = {SISSA;33/00/M}, year = {2002}, publisher = {SISSA Library}, doi = {10.1006/jdeq.2001.4066}, url = {http://hdl.handle.net/1963/1491}, author = {Jean-Marc Mercier and Benedetto Piccoli} }