@misc{AMUC_1989__54-55_186041,
     title = {[unknown]},
     journal = {Acta mathematica Universitatis Comenianae},
     pages = {281--284},
     year = {1989},
     volume = {54-55},
     url = {http://geodesic.mathdoc.fr/item/AMUC_1989__54-55_186041/}
}