1. Eckhardt, T.K. Cold Roll Forming Theory and Application. Bulletin 709/872 (1973). The Yoder Company, Cleveland, Ohio, p 1.
2. Pai D., Prediction of Metal Flow and Roll Pass Design in Roll Forming, Masters Thesis, The Ohio State University, Columbus, USA, 1994.
3. Images: www.hadleygroup.co.uk (Hadley Industries PLC). Accessed on 18 November 2005.
4. Halmos, G.T. High Production Roll Forming, Society of Manufacturing Engineers (1984) Michigan.
5. Hadley Industries PLC, PO Box 92, Downing Street, Smethwick, Birmingham, B66 2PA. United Kingdom