@article{GFA_1996__6_1_58221,
     author = {Z.J. Liu and P. Xu},
     title = {Exact {Lie} {Bialgebroids} and {Poisson} {Groupoids.}},
     journal = {Geometric and functional analysis},
     pages = {138--145},
     year = {1996},
     volume = {6},
     number = {1},
     zbl = {0869.17016},
     url = {http://geodesic.mathdoc.fr/item/GFA_1996__6_1_58221/}
}