@article{AL_2006_45_5_a0,
     author = {A. N. Gavryushkin},
     title = {Complexity of {Ehrenfeucht} models},
     journal = {Algebra i logika},
     pages = {507--519},
     year = {2006},
     volume = {45},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2006_45_5_a0/}
}