CONSTRUCTION OF FUNCTION-SPACES BY MEANS OF THE LAPLACIAN AND THE AVERAGING METHOD ArticleZHIDKOV G.V.Differential Equations. Vol. 20. 1984. P.. 477-485
VARIATIONAL METHOD FOR SOLVING BOUNDARY-VALUE-PROBLEMS FOR THE WAVE-EQUATION ArticleFILIPPOV V.M.Differential Equations. Vol. 20. 1984. P.. 1401-1407