Can anyone provide a good academic paper on leaky gut?

I have been on this subreddit for a couple months now, and I keep hearing about leaky gut, dysbiosis and associated symptoms and treatments, but never with solid data to back it up. I am in med school right now and doing research on the side, so please don’t shy away from actual articles, not the webmd healthywhatever websites. I am struggling to understand if this is a real, clearly defined entity or just findings in animal models and associations specifically for people with disorders like Parkinson’s, IBD, rheumatic diseases etc. Thanks a lot!