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4. R. Gasch, Kleiner Beitrag zur Behandlung des dynamischen Verhaltens einer rotierenden Welle mit angerissenem Querschnitt. 4 (A Short Paper on the Dynamics of a Rotating Shaft with a Crack), ILR-Bericht 8, TU Berlin, 1975 (ISBN 3 7983 0551 X).
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