@article{DA_2008_15_4_a3,
     author = {P. V. Martyugin},
     title = {Lower bounds for the length of the shortest carefully synchronizing words for two- and three-letter partial automata},
     journal = {Diskretnyj analiz i issledovanie operacij},
     pages = {44--56},
     publisher = {mathdoc},
     volume = {15},
     number = {4},
     year = {2008},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DA_2008_15_4_a3/}
}