@article{10_4153_CMB_1975_120_x,
     author = {Kotzig, Anton},
     title = {Degrees of {Vertices} in a {Friendship} {Graph}},
     journal = {Canadian mathematical bulletin},
     pages = {691--693},
     year = {1975},
     volume = {18},
     number = {5},
     doi = {10.4153/CMB-1975-120-x},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1975-120-x/}
}