The Perfect Lattices Gamma(Un), and the Covering Density of Gamma(Un). - Evgenii P. Baranovskii (Eur. J. Comb., 1994)

Non-rigidity Degree of a Lattice and Rigid Lattices. - Evgenii P. Baranovskii; Viatcheslav P. Grishukhin (Eur. J. Comb., 2001)