Bibliography tools for easy referencing of an academic paper

Nowadays, when I quickly need to write a report or paper with academic references, my methodology is to first complete a list of references and try to download all the papers and other sources that I think I might use. Since it is very convenient to write using the Markdown language and use BibTeX source files for citations (since this allows for later easy formatting and reformatting) it helps to first get the BibTeX references for each paper.

This is easiest using doi2bib which provides the BibTeX from a DOI number or address. The DOI is a generally used universal identifier for much technical literature. Incidentally, the easiest tool for obtaining the papers themselves is the cooperative or pirate (depending on your point of view) site Sci-Hub which uses the same DOI to get the paper itself from behind the paywall. Naturally, Sci-Hub is probably in serious violation of ordinary copyright but I think the users, especially if they are already entitled to access the material they seek but in a less convenient way, might consider it to be fair use and moderately unobjectionable.