@article{GDZPPN00036424X,
title = {Penny-Packing and Two-Dimensional Codes.},
journal = {Discrete \& computational geometry},
volume = {5},
year = {1990},
pages = {1-12},
zbl = {0686.52010},
url = {http://dml.mathdoc.fr/item/GDZPPN00036424X}
}
Sloane, N.J.A.; Graham, R.L. Penny-Packing and Two-Dimensional Codes.. Discrete & computational geometry, Tome 5 (1990) pp. 1-12. http://gdmltest.u-ga.fr/item/GDZPPN00036424X/