Gabriel Ciobanu Gheorghe Paun Fundamentals of Computation Theory, 12th International Symposium, FCT '99, Iasi, Romania, August 30 - September 3, 1999, Proceedings FCT Lecture Notes in Computer Science 1684 Springer 1999 3-540-66412-2 https://doi.org/10.1007/3-540-48321-7 db/conf/fct/fct99.html