@article{10_21136_CMJ_1970_100949,
     author = {Chv\'atal, V\'aclav},
     title = {A remark on a problem of {Harary}},
     journal = {Czechoslovak Mathematical Journal},
     pages = {109--111},
     publisher = {mathdoc},
     volume = {20},
     number = {1},
     year = {1970},
     doi = {10.21136/CMJ.1970.100949},
     mrnumber = {0266791},
     zbl = {0197.50203},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1970.100949/}
}