@article{JIS_2015__18_6_a1,
     author = {Gent, Ian and Kitaev, Sergey and Konovalov, Alexander and Linton, Steve and Nightingale, Peter},
     title = {$S$-crucial and bicrucial permutations with respect to squares},
     journal = {Journal of integer sequences},
     publisher = {mathdoc},
     volume = {18},
     number = {6},
     year = {2015},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2015__18_6_a1/}
}