(This page is a work in progress. I will update it with more suggestions soon.)
I recommend using this list as a starting point for an initial paper, but you are welcome to look elsewhere for additional papers on a similar subject.
One place to find papers on learning theory is the proceedings of the Conference on Learning Theory (COLT; formerly known as the Conference on Computational Learning Theory).
Another conference to check out is the International Conference on Algorithmic Learning Theory.
Of course, other conferences in theoretical computer science (FOCS, STOC, SODA, etc.) also occasionally have papers on learning theory.
The Conference on Neural Information Processing Systems (now known as NeurIPS) and the International Conference om Machine Learning (ICML) are general machine learning conferences that also feature many papers on theory.
Occasionally, some journals (like JMLR, JCSS, Algorithmica) have special issues on learning theory. A good way to find this is to search “special issue” and “learning theory” on your favorite search engine. (Perhaps also throw in the name of the journal in the query.) These same journals are also likely to have regular journal articles on learning theory (not as part of a special issue).