@article{BMMS_2012_35_2A_a1,
     author = {Siu Lun Ma},
     title = {Difference {Sets} and {Sequences}},
     journal = {Bulletin of the Malaysian Mathematical Society},
     year = {2012},
     volume = {35},
     number = {2A},
     url = {http://geodesic.mathdoc.fr/item/BMMS_2012_35_2A_a1/}
}