@misc{AMUC_1987__52-53_186011,
     title = {[unknown]},
     journal = {Acta mathematica Universitatis Comenianae},
     pages = {249--274},
     publisher = {mathdoc},
     volume = {52-53},
     year = {1987},
     url = {http://geodesic.mathdoc.fr/item/AMUC_1987__52-53_186011/}
}