@article{AL_2008_47_6_a2,
     author = {A. V. Karpenko},
     title = {Weak interpolation in extensions of the logics $S4$ and~$K4$},
     journal = {Algebra i logika},
     pages = {705--722},
     publisher = {mathdoc},
     volume = {47},
     number = {6},
     year = {2008},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2008_47_6_a2/}
}