Carefully, Paarthurnax goes through his memories. Having lived in Skyrim most of his long life, he's of course more familiar with their books than others. Still, he's certain he can recall if he delves through his thoughts.

"I believe there is a treatise on the use of calcinators... The Calcintator Treatise, geh. I am afraid the author escapes me in this moment. Ah." A pleased tone shifts through his voice. "Athyn Muendil wrote a tale, the Cake and the Diamond. It has been some time since I have read it last, but I believe it involves some talk of invisibility."

There are others, of course, but Vivic's sermons have always been somewhat difficult to parse for some. Later, perhaps he'll recommend them, but there's no need to rush such things.