@article{AL_2015_54_2_a9,
     author = {A. N. Khisamiev},
     title = {Universal functions over trees},
     journal = {Algebra i logika},
     pages = {283--291},
     publisher = {mathdoc},
     volume = {54},
     number = {2},
     year = {2015},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2015_54_2_a9/}
}