Those experts seems know more underlying facts of Agile practices or frameworks and so on, referring to some articles or publications are quite normal. I was astonished, coz it would be amazing if they read all those reference documents. Perhaps that’s said "one is never too old to learn". Let’s keep learning, forever!
If you have any questions in your mind regarding Agile, raise it up, I’ll try to ask. My mind is so slow these days, maybe I need a good rest 😦