@article{AL_2010_49_2_a2,
     author = {A. V. Zhukov and O. V. Kudinov and V. L. Selivanov},
     title = {Definability of closure operations in the $h$-quasiorder of labeled forests},
     journal = {Algebra i logika},
     pages = {181--194},
     publisher = {mathdoc},
     volume = {49},
     number = {2},
     year = {2010},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2010_49_2_a2/}
}