@article{BMMS_2013_36_1_a17,
     author = {Lei Sun},
     title = {Combinatorial {Results} for {Certain} {Semigroups} of {Transformations} {Preserving} {Orientation} and a {Uniform} {Partition}},
     journal = {Bulletin of the Malaysian Mathematical Society},
     year = {2013},
     volume = {36},
     number = {1},
     url = {http://geodesic.mathdoc.fr/item/BMMS_2013_36_1_a17/}
}