@article{GDZPPN00036309X, title = {Some Basic Properties of Packing and Covering Constants.}, journal = {Discrete \& computational geometry}, volume = {1}, year = {1986}, pages = {183-193}, zbl = {0599.52006}, url = {http://dml.mathdoc.fr/item/GDZPPN00036309X} }
Groemer, H. Some Basic Properties of Packing and Covering Constants.. Discrete & computational geometry, Tome 1 (1986) pp. 183-193. http://gdmltest.u-ga.fr/item/GDZPPN00036309X/