@article{KYB_1991__27_6_a3,
     author = {Thierfelder, J\"org},
     title = {Separation theorems for sets in product spaces and equivalent assertions},
     journal = {Kybernetika},
     pages = {522--534},
     publisher = {mathdoc},
     volume = {27},
     number = {6},
     year = {1991},
     mrnumber = {1150940},
     zbl = {0778.46005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/KYB_1991__27_6_a3/}
}