Application of the Ritz method to the solution of parabolic boundary value problems of arbitrary order in the space variables. (English). In: Ráb, Miloš and Vosmanský, Jaromír (eds.): Proceedings of Equadiff III. 3rd Czechoslovak Conference on Differential Equations and Their Applications. Brno, Czechoslovakia, August 28 - September 1, 1972. Univ. J. E. Purkyně - Přírodovědecká fakulta, Brno, 1973. pp. 255-260