http://www.fraw.org.uk/mei/archive/handouts/ssp/sspji-05.pdf
http://www.resistorguide.com/pictures/wirewound_resistor.png
http://www.resistorguide.com/wirewound-resistor/
http://www.penbro.co.za/resistors/wire-wound-resistors2.pdf
https://hackaday.com/2018/07/21/wire-wound-resistors-on-your-own/