@article{DAN_1979_247_6_a4,
     author = {L. A. Grigorenko},
     title = {Symmetric events in certain {Markov} chains},
     journal = {Doklady Akademii Nauk},
     pages = {1305--1308},
     year = {1979},
     volume = {247},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1979_247_6_a4/}
}