@article{JIS_2010__13_6_a5,
     author = {Mansour, Toufik and Shattuck, Mark},
     title = {Counting peaks and valleys in a partition of a set},
     journal = {Journal of integer sequences},
     publisher = {mathdoc},
     volume = {13},
     number = {6},
     year = {2010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2010__13_6_a5/}
}