@article{10_4153_CMB_1969_012_7,
     author = {Brown, B.},
     title = {An {Approximation} to {{X,} {Y}}},
     journal = {Canadian mathematical bulletin},
     pages = {133--137},
     year = {1969},
     volume = {12},
     number = {2},
     doi = {10.4153/CMB-1969-012-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1969-012-7/}
}