The barrier cone of a convex set and the closure of the cover. Bair, J.; Dupin, J.C. — 1999 Journal of Convex Analysis
Les (e...,...,e...)-convexes de R...; la proprieté d'intersection et les filtres maximaux de convexes. G. Coquet; J.C. Dupin; R. Fourneau — 1984 Mathematica Scandinavica