@article{10_4153_CMB_1963_024_5,
     author = {Erd\"os, P. and R\'enyi, A.},
     title = {Remarks on a {Problem} of {Obreanu}},
     journal = {Canadian mathematical bulletin},
     pages = {267--273},
     year = {1963},
     volume = {6},
     number = {2},
     doi = {10.4153/CMB-1963-024-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1963-024-5/}
}