@article{ZNSL_1987_158_a3,
     author = {S. S. Vallander},
     title = {Occupation times for countable {Markov} {chains.~IV.} {Chains} on a general tree},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {39--44},
     year = {1987},
     volume = {158},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1987_158_a3/}
}