@article{AUCMP_1991_32_2_a0,
     author = {Balcar, Bohuslav},
     title = {Foreword},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {3},
     year = {1991},
     volume = {32},
     number = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUCMP_1991_32_2_a0/}
}