1. 1979. London: Department of Industry, HMSO. Business Monitor PQ 450
2. Hole , L. G. Kann , G. Dawkins , P. J. F. and Reynolds , R. J. W. International Rubber Conf. pp.1–6. Brighton: Plastics and Rubber Inst. paper F3
3. SATRA Method AM1, equivalent to BS5131: Subsections 1.1.2 and 1.1.3
4. SATRA Method AM3, equivalent to BS5131: Subsection 1.1.1