@article{biheyting,
    Author = {Reyes, Gonzalo E. and Zolfaghari, Houman},
    File = {Bi-Heyting algebras, toposes and modalities - Reyes, Zolfaghari (0) (0) - a - a - g.pdf},
    ISSN = {0022-3611},
    Journal = {Journal of Philosophical Logic},
    Keywords = {Heyting algebras},
    Language = {English},
    Number = {1},
    Pages = {25-43},
    Publisher = {Kluwer Academic Publishers},
    Title = {Bi-Heyting algebras, toposes and modalities},
    URL = {http://dx.doi.org/10.1007/BF00357841},
    Volume = {25},
    Year = {1996},
    bdsk-url-1 = {http://dx.doi.org/10.1007/BF00357841},
    date-added = {2013-05-18 08:28:36 +0000},
    date-modified = {2013-05-18 08:29:13 +0000},
    doi = {10.1007/BF00357841}
}

@article{biheyting, Author = {Reyes, Gonzalo E. and Zolfaghari, Houman}, File = {Bi-Heyting algebras, toposes and modalities - Reyes, Zolfaghari (0) (0) - a - a - g.pdf}, ISSN = {0022-3611}, Journal = {Journal of Philosophical Logic}, Keywords = {Heyting algebras}, Language = {English}, Number = {1}, Pages = {25-43}, Publisher = {Kluwer Academic Publishers}, Title = {Bi-Heyting algebras, toposes and modalities}, URL = {http://dx.doi.org/10.1007/BF00357841}, Volume = {25}, Year = {1996}, bdsk-url-1 = {http://dx.doi.org/10.1007/BF00357841}, date-added = {2013-05-18 08:28:36 +0000}, date-modified = {2013-05-18 08:29:13 +0000}, doi = {10.1007/BF00357841} }