@article{JAC_2006__24_2_a4,
     author = {Sagan, Bruce E. and Vatter, Vincent},
     title = {The {M\"obius} function of a composition poset},
     journal = {Journal of Algebraic Combinatorics},
     pages = {117--136},
     publisher = {mathdoc},
     volume = {24},
     number = {2},
     year = {2006},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JAC_2006__24_2_a4/}
}