@article{EngelfrietMS09Deciding, author = {Joost Engelfriet and Sebastian Maneth and Helmut Seidl}, title = {Deciding equivalence of top-down {XML} transformations in polynomial time}, journal = {J. Comput. Syst. Sci.}, year = 2009, pages = {271--286}, volume = {75}, number = {5}, doi = {10.1016/j.jcss.2009.01.001}, }