@article{ZNSL_1997_241_a5,
     author = {N. K. Kossovski and A. V. Tishkov},
     title = {Gradable logical values for knowlege representation},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {135--149},
     year = {1997},
     volume = {241},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1997_241_a5/}
}