@article{SM_1991_68_1_a13,
     author = {M. V. Zakharyaschev},
     title = {Modal companions of superintuitionistic logics: syntax, semantics, and preservation theorems},
     journal = {Sbornik. Mathematics},
     pages = {277--289},
     publisher = {mathdoc},
     volume = {68},
     number = {1},
     year = {1991},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1991_68_1_a13/}
}