@article{CSIS_2012_9_3_a7,
     author = {Jan Travn{\i}cek and Jan Janousek and Borivoj Melichar},
     title = {Indexing {Ordered} {Trees} for {(Nonlinear)} {Tree} {Pattern} {Matching} by {Pushdown} {Automata}},
     journal = {Computer Science and Information Systems},
     publisher = {mathdoc},
     volume = {9},
     number = {3},
     year = {2012},
     url = {http://geodesic.mathdoc.fr/item/CSIS_2012_9_3_a7/}
}