Currently I'm in the last year of the Physics course and I'm interested in working on some undergraduate research project. At first I was suggested to work with statistical physics, but I believe I would prefer working with General Relativity. From the point of view of background I do have a good mathematical background. Indeed the course I'm taking is a Mathematical Physics course, so I already studied analysis, advanced linear algebra, differential geometry, and so on. So, the fact that GR requires differential geometry is not a problem for me. My problem is picking a specific topic. What I want is to find one article to work with, so that the project would be to study GR and then study the topic treated on the article. My main idea was something about gravitational waves and/or black holes. I've searched a lot but didn't find much. I want one article to work with which approaches the problem in a theoretical way, that is, with the equations rather than with simulations or experiments. Are there some articles on gravitational waves and/or black holes which fits this description and could be used for one undergraduate research project? If not, what would be another topic that could be tackled with a mathematical approach, and what would be some article on the topic that could be used for the project?