@article{CTGDC_1985__26_2_115_0,
     author = {Niefield, S. B. and Rosenthal, K. I.},
     title = {A note on the algebraic de {Morgan's} law},
     journal = {Cahiers de Topologie et G\'eom\'etrie Diff\'erentielle Cat\'egoriques},
     pages = {115--120},
     publisher = {Dunod \'editeur, publi\'e avec le concours du CNRS},
     volume = {26},
     number = {2},
     year = {1985},
     mrnumber = {794750},
     zbl = {0575.13002},
     language = {en},
     url = {http://archive.numdam.org/item/CTGDC_1985__26_2_115_0/}
}