@article{SLC_1987_16_a6,
     author = {Luigi Azzena and Francesco Piras},
     title = {The {Duality} between {Incidence} {Algebras} and {Coalgebras.} {A} {Few} {Remarks}},
     journal = {S\'eminaire lotharingien de combinatoire},
     year = {1987},
     volume = {16},
     url = {http://geodesic.mathdoc.fr/item/SLC_1987_16_a6/}
}