@article{BMMS_2011_34_1_a7,
     author = {Muhammad Shabir and Asghar Khan},
     title = {Fuzzy {Quasi-Ideals} of {Ordered} {Semigroups}},
     journal = {Bulletin of the Malaysian Mathematical Society},
     year = {2011},
     volume = {34},
     number = {1},
     url = {http://geodesic.mathdoc.fr/item/BMMS_2011_34_1_a7/}
}