@article{ZNSL_1989_177_a3,
     author = {S. S. Vallander},
     title = {Occupation times for non-homogenious {Markov} chains with discrete time},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {37--45},
     publisher = {mathdoc},
     volume = {177},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1989_177_a3/}
}