@article{JIS_2014__17_1_a3,
     author = {Hu,  Yangzhou},
     title = {On the number of fixed-length semiorders},
     journal = {Journal of integer sequences},
     year = {2014},
     volume = {17},
     number = {1},
     zbl = {1292.05026},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2014__17_1_a3/}
}