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3. Donnell-Type Equations for Bending and Buckling of Orthotropic Conical Shells
4. Schiffner K. Über das elastische Stabilitatsverhalten diinnwandiger Orthotroper Kegelschalen unter Axiallast und Innendruck. Presented at the Annual Meeting of the Wissenschaftliche Gesellschaft fur Luft- und Raumfahrt, Braunschweig, 1962.