1. Koenigsberger, F.: ‘Rigidity of machine tool beds’, Machinery, London 1938 June, 9),52, p. 339 No. 1
2. Koenigsberger, F.: ‘Must a rigid machine tool be heavy?’, Machinery, London 1940 April, 18),56,
3. Opitz, H.: Performance of machine tool testing,
4. Crossley, F.R.E.: Dynamics in machinery,