@article{AL_1992_31_5_a2,
     author = {S. I. Mardaev},
     title = {Fixed points of modal schemes},
     journal = {Algebra i logika},
     pages = {493--498},
     publisher = {mathdoc},
     volume = {31},
     number = {5},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1992_31_5_a2/}
}