@article{10_1017_S0017089500004146,
     author = {Smith, D. H.},
     title = {Perfect codes in the graphs {Ok} and {L(Ok)}},
     journal = {Glasgow mathematical journal},
     pages = {169--172},
     year = {1980},
     volume = {21},
     number = {1},
     doi = {10.1017/S0017089500004146},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500004146/}
}