Line Density Conversion Calculator
- On-line conversion calculator for units of line density, including a special calculator for the conversion of textile yarns. From Cleave Books.
- http://www.cleavebooks.co.uk/scol/ccdenlin.htm

Ring Spinning Technology
- Information resource about the processes and technologies in use with ring spinning of industrial yarns.
- http://ringspinning.bravehost.com/

Universal Yarn Care Symbols
- List of universal yarn care symbols and definitions as used by the yarn spinning and textile industry. From Trendsetter Yarns.
- http://www.trendsetteryarns.com/symbols.htm

Fibers & Yarns
- From the US Customs Service (July 2006). Publication on the construction and classification of fibers and yarns under the harmonized system. Detailed technical definitions and specifications.
- http://www.cbp.gov/linkhandler/cgov/toolbox/legal/informed_compliance_pubs/icp005r2.ctt/icp005.pdf

Yarn Calculator
- Universal yarn number equivalent calculator. From Service Thread Manufacturing Co.
- http://www.servicethread.com/Calculator/tabid/26/Default.aspx

Swiss Yarn Foundation
- Organization for individuals and companies, aiming to promote information exchange, education and training for mill employees. Detailed history of the Swiss textile industry. English, German and French.
- http://www.swissyarn.ch/