Slawomir Staworko Grégoire Laurence Aurélien Lemay Joachim Niehren Equivalence of Deterministic Nested Word to Word Transducers. 310-322 2009 FCT http://dx.doi.org/10.1007/978-3-642-03409-1_28 conf/fct/2009 db/conf/fct/fct2009.html#StaworkoLLN09