Ethernet Standards: Stranded Cable ? >10m

Hi All,

I was wondering if any could help me find the formal standard (e.g. IEEE) which provides the calculations for running stranded cable >10m, e.g. 15m.

The website below provides the calculation but no reference from where it's been taken from, I've looked a few other sites which have the same calculations but no formal reference.

https://www.flukenetworks.com/blog/cabling-chronicles/considerations-choosing-stranded-vs-solid-cable#:~:text=When%20it%20comes%20to%20de,no%20de%2Drating%20at%20all

If someone could point in the right direction it'd be appreciated.

Thanks

Swain90