@article {IOPORT.05752635,
    author       = {Chigansky, Pavel and Van Handel, Ramon},
    title        = {A complete solution to blackwell's unique ergodicity problem for hidden Markov chains.},
    year         = {2009},
    journal      = {Computing Research Repository (CoRR)},
    volume       = {2009},
    pages        = {Article No. 0910.3603},
    publisher    = {Association for Computing Machinery, New York, NY; Cornell University, Ithaka, NY},
    identifier   = {05752635},
}