Finding research papers for undergraduate research
Academic knowledge is connected through a web of citations and references. Once you have a piece of that web, you can follow the threads towards other papers. 

Start at the Wikipedia Page, specifically the Notes and References sections. 

See if any of the links there take you to a PDF... look for DOI numbers, or PDF in the link. If not, use Google to try to find a paper. Start reading it. 

Look for a word or phrase you recognize, and want to know more about, or something seems about the direction you want to go. Likely, this will be cited... look in the references section of that paper, then google that paper (or follow the kindly provided links). 

You're traversing a web of references, so you'll come back to the same papers sometimes. If I were you, I'd keep notes about each of the papers I look into.


Title
Authors
Link to PDF
Single sentence summary. 


Once you've been doing this for a day or so, you'll notice that there are some authors who have a good connection to the topic you're interested in. Look up their university web page; Often they'll have a list of their papers. 

Essentially, you are crawling the web of references yourself. Keep following the links, keep track of where you've been, where you want to go. 



Oh, one other thing: Google Scholar is a decent choice for getting an overview of a topic because it will sort papers by reference count: Highly cited papers often contain important information; Be it an excellent summary or a novel insight.