1. Manifolds, Tensor Analysis and Applications.;Abraham,1988
2. An intrinsic definition of the Colombeau algebra of generalized functions.;Aragona;Analysis Math.,1991
3. [1] Approximate symmetries.;Baikov;Mat Sbor.,1988
4. [2] Perturbation methods in group analysis.;Baikov;J. Sov. Math.,1991
5. A Nonlinear Theory of Generalized Functions.;Biagioni,1990