The International Bureau For The Standardisation of Man-Made Fibres (BISFA) (2009), Terminology of man-made fibres(PDF), p. 49, archived from the original(PDF) on 2015-11-23, retrieved 2013-08-04
The International Bureau For The Standardisation of Man-Made Fibres (BISFA) (2009), Terminology of man-made fibres(PDF), p. 49, archived from the original(PDF) on 2015-11-23, retrieved 2013-08-04