Smithsonian: X-Rays Reveal „Hidden Library“ on the Spines of Early Books

The words of the 8th-century Saint Bede are among those that have been found by detecting iron, copper and zinc – constituents of medieval ink …

Siehe: http://www.smithsonianmag.com/smart-news/x-rays-reveal-hidden-library-spines-early-books-180959317/?no-ist

Auch:

X-Rays Expose a Hidden Medieval Library

https://www.theguardian.com/books/2016/jun/04/x-rays-reveal-medieval-manuscripts