Henning Bordihn Henning Fernau Markus Holzer Vincenzo Manca Carlos Martín-Vide Iterated sequential transducers as language generating devices. 67-81 2006 369 Theor. Comput. Sci. 1-3 http://dx.doi.org/10.1016/j.tcs.2006.07.059 db/journals/tcs/tcs369.html#BordihnFHMM06