Are there tools to find a subset of references shared by two or more publications? Doing a literature review on a topic that is new to me at the moment, I am especially interested in papers that are cited across several of the papers I'm currently focussing on.
I was wondering if there is a tool out there, which I can feed with a list of the papers I'm reading, and that will provide me with a set of shared references. 
Looking into Web of Science, Scopus and Google Scholar, I couldn't find something resembling such an option, but maybe I have just overseen it. 
Googling for a tool like this proved also difficult, maybe because I couldn't find the propper search terms.

I know that there is an api for Scopus, with which one could probably write a Python Script to perform such a task, but I rather not reinvent the wheel and waste time (although it'd probably be fun to check out the Scopus api).
The process of finding the intersection of the references in a given set of papers is known as bibliographic coupling and was first proposed by M. M. Kessler in 1963 in a paper that sadly remains locked behind a paywall 52 years later. Kessler was thinking about doing this for pairs of papers but of course you could do this for an arbitrary number. What might also be interesting would be to look for the set of papers reachable by following citation trails backward in time through any number of steps. 

I am unaware of any on-line tools that perform this type of comparison for you, though it would not be hard to build such a thing if you had access to a big enough citation graph.