@article{10_4153_CMB_1978_068_1,
     author = {Sridharan, M. R.},
     title = {Note on an {Asymptotic} {Formula} for a {Class} of {Digraphs}},
     journal = {Canadian mathematical bulletin},
     pages = {377--381},
     year = {1978},
     volume = {21},
     number = {3},
     doi = {10.4153/CMB-1978-068-1},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1978-068-1/}
}