@article{JAC_2007__26_2_a1,
     author = {Ehrenborg, Richard and Karu, Kalle},
     title = {Decomposition theorem for the cd-index of {Gorenstein} posets},
     journal = {Journal of Algebraic Combinatorics},
     pages = {225--251},
     publisher = {mathdoc},
     volume = {26},
     number = {2},
     year = {2007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JAC_2007__26_2_a1/}
}