@ARTICLE{Istrail1978b, author = {Istrail, Sorin}, title = {Contextual grammars with regular choice}, journal = {Studii si Cercetari Matematice}, year = {1978}, volume = {30}, pages = {287--294}, number = {3}, owner = {Derek}, timestamp = {2012.05.08}, category = {Theory of Computation} }