@article{MS2_1990__66_1_167107,
     author = {Jan Boman},
     title = {Smoothness of sums of convex sets with real analytic boundaries.},
     journal = {Mathematica Scandinavica},
     pages = {225--230},
     publisher = {mathdoc},
     volume = {66},
     number = {1},
     year = {1990},
     zbl = {0738.52003},
     url = {http://geodesic.mathdoc.fr/item/MS2_1990__66_1_167107/}
}