@article{05014477, title = {Difference density and aperiodic sum-free sets.}, journal = {Integers}, volume = {5}, year = {2005}, zbl = {1107.11013}, language = {en}, url = {http://dml.mathdoc.fr/item/05014477} }
Calkin, Neil J.; Finch, Steven R.; Flowers, Timothy B. Difference density and aperiodic sum-free sets.. Integers, Tome 5 (2005) . http://gdmltest.u-ga.fr/item/05014477/