As a non-academic, how do I find papers that reference a certain article? I have recently read an interesting article on number theory, published in a well-known mathematics journal. As a keen amateur mathematician, I have tried to develop some of the ideas presented in the paper. Surprisingly, I have come to a remarkable conclusion that might be worth publishing. Naturally, I first wanted to make sure that this has not been published before, so I tried to find papers that referenced the original article.

The issue is that websites that index or catalog scholarly material are off-limits to non-academics. In particular, in order to find references to certain papers or authors, one must first log in with an institution's credentials, which obviously I do not possess. What are my options? Do I:


write up my research anyway and try to publish it, with the risk of wasting everybody's time if a similar publication has already been made,
waste the original author's time by asking him to send me a list of references to his article (with a high probability of having my request immediately discarded), or
pay a high subscription fee to these cataloging websites in order to find what I'm looking for?


Is there another way for me to go about this?
Google Scholar can get you quite far.

Go to scholar.google.com and paste in the full title of the paper you're looking for.  Here's one of mine:



Click the "cited by" link (highlighted) and you'll get a list of works citing the paper you're interested in.  Some of these will be papers, some won't, and Google's indexing isn't quite the same as some of the other sources.  But it's close.  For each of the citing papers, there's an "All n versions" link.  Browsing those versions will often get you to a legitimate copy from the author's institutional repository (see the right-hand column), ArXiv, or various other sources; the Unpaywall browser extension can also help track these down.