Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
$\begingroup$Thanks! It is useful indeed. I think the example of the infinite line of charge in the 1st article is a good starting point for me (as a retired electrical engineer) to learn with time this subject.$\endgroup$
$\begingroup$I have updated the 1st link, please recheck it, also here is another link for the same article which looks like slides for a talk hep.wisc.edu/cteq11/lectures/Olness_DimReg.pdf$\endgroup$