2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/735The method of negative density is presented which allows to obtain the analytical solutions for potential energy of new kinds of homogeneous and ihhomogeneous self-gravitating bodies. The homogeneous bispherical concavo-convex lens is considered in particular.4 pages, 3 figuresAstrophysicsClassical Physicstext