@article{ARM_1983__19_3_a5,
     author = {Niederle, Josef},
     title = {Conditions for trivial principal tolerances},
     journal = {Archivum mathematicum},
     pages = {145--152},
     publisher = {mathdoc},
     volume = {19},
     number = {3},
     year = {1983},
     mrnumber = {725197},
     zbl = {0538.08002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_1983__19_3_a5/}
}