@article{10_4153_CMB_1965_018_9,
     author = {Schaer, J.},
     title = {The {Densest} {Packing} of 9 {Circles} in a {Square}},
     journal = {Canadian mathematical bulletin},
     pages = {273--277},
     year = {1965},
     volume = {8},
     number = {3},
     doi = {10.4153/CMB-1965-018-9},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1965-018-9/}
}