@article{10_21136_CMJ_1974_101250,
     author = {Burshtein, Nechemia and Sch\"onheim, Johanan},
     title = {On exactly covering systems of congruences having moduli occurring at most twice},
     journal = {Czechoslovak Mathematical Journal},
     pages = {369--372},
     publisher = {mathdoc},
     volume = {24},
     number = {3},
     year = {1974},
     doi = {10.21136/CMJ.1974.101250},
     mrnumber = {0352033},
     zbl = {0311.10002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1974.101250/}
}