@article{SLC_1987_18_a6,
     author = {Francois Bergeron and Gilbert Labelle and Pierre Leroux},
     title = {Functional {Equations} for {Data} {Structures}},
     journal = {S\'eminaire lotharingien de combinatoire},
     publisher = {mathdoc},
     volume = {18},
     year = {1987},
     url = {http://geodesic.mathdoc.fr/item/SLC_1987_18_a6/}
}