Jie Fu, Jeffrey Heinz, Herbert G. Tanner. An Algebraic Characterization of Strictly Piecewise Languages. In Mitsunori Ogihara, Jun Tarui, editors, Theory and Applications of Models of Computation - 8th Annual Conference, TAMC 2011, Tokyo, Japan, May 23-25, 2011. Proceedings. Volume 6648 of Lecture Notes in Computer Science, pages 252-263, Springer, 2011. [doi]