1. A Koewius, Aluminum-spaceframe-technology: light-weight construction reaches a new dimension in automotive mass production, Aluminium 70 (1/2) (1994) 38–48; (3/4) (1994) 144–156 (in German).
2. Hydroforming—a method to manufacture light-weight parts;Dohmann;J. Mater. Process. Technol.,1996
3. A. Neubauer, P.J. Bolt, Hydrostatic forming of hollow parts: state of the art and future, in: H.J.J. Kals, et al. (Eds.) Proceedings of the Fourth Conference on Sheet Metal 1996, vol. 2, University of Twente, NL, 1996, pp. 111–122.
4. M. Geiger, F. Vollertsen, Production of hollow structures by hydroforming. German patent application P 195 35 870.8, (1995).
5. New ideas on hydroforming (in German);Geiger;Blech Rohre Profile,1996