1. W. V. Morgan,De Tex-Textllis,1978,No. 3,13.
2. P. Lennox-Kerr.Wool Rec.1976,130, July, 52.
3. Open-end Spinning Machine System (DREF), trade literature (1976).
4. G. W. Walls in 'The Yarn Revolution' (edited by P. W. Harrison), the Textile Institute, Manchester, 1976, p. 142.
5. Platt International Ltd and F. A. Greenwood. B.P. 1,347,490 (20 Feb., 1974).