@article{MS2_1969__25_166112,
     author = {Bernt Lindstr\"om},
     title = {On {Group} and {Nongroup} {Perfect} {Codes} in q {Symbols.}},
     journal = {Mathematica Scandinavica},
     pages = {149--158},
     publisher = {mathdoc},
     volume = {25},
     year = {1969},
     zbl = {0205.46903},
     url = {http://geodesic.mathdoc.fr/item/MS2_1969__25_166112/}
}