@article{01538458, title = {Research notes on a density problem of Erd\H os.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {22}, year = {1999}, pages = {655-658}, doi = {10.1155/S0161171299226555}, zbl = {0972.11009}, language = {en}, url = {http://dml.mathdoc.fr/item/01538458} }
Akbik, Safwan. Research notes on a density problem of Erdős.. International Journal of Mathematics and Mathematical Sciences, Tome 22 (1999) pp. 655-658. doi : 10.1155/S0161171299226555. http://gdmltest.u-ga.fr/item/01538458/