@article{Greibach:1968,
    Abstract = {A general set of conditions is given under which a property is undecidable for a family of languages. Examples are given of the application of this result to wellknown families of languages.},
    Author = {Greibach, Sheila},
    File = {A note on undecidable properties of formal languages - Greibach (0) (0) - a - a - b.pdf},
    ISSN = {1433-0490},
    Journal = {Math. Systems Theory},
    Month = {March},
    Number = {1},
    Pages = {1--6},
    Title = {A note on undecidable properties of formal languages},
    URL = {http://dx.doi.org/10.1007/BF01691341},
    Volume = {2},
    Year = {1968},
    bdsk-url-1 = {http://dx.doi.org/10.1007/BF01691341},
    date-added = {2016-01-12 15:09:12 +0000},
    date-modified = {2016-01-12 15:57:01 +0000},
    doi = {10.1007/BF01691341}
}

@article{Greibach:1968, Abstract = {A general set of conditions is given under which a property is undecidable for a family of languages. Examples are given of the application of this result to wellknown families of languages.}, Author = {Greibach, Sheila}, File = {A note on undecidable properties of formal languages - Greibach (0) (0) - a - a - b.pdf}, ISSN = {1433-0490}, Journal = {Math. Systems Theory}, Month = {March}, Number = {1}, Pages = {1--6}, Title = {A note on undecidable properties of formal languages}, URL = {http://dx.doi.org/10.1007/BF01691341}, Volume = {2}, Year = {1968}, bdsk-url-1 = {http://dx.doi.org/10.1007/BF01691341}, date-added = {2016-01-12 15:09:12 +0000}, date-modified = {2016-01-12 15:57:01 +0000}, doi = {10.1007/BF01691341} }