Long before ruled notebooks hit the shelves, medieval writers lined, laid out, and folded their own parchment.
Three scribes at work by PRE-ROMANESQUE SCULPTOR, German
The Work of a Scribe
Making Medieval Manuscripts – Brewminate: A Bold Blend of News and Ideas
Form (Chapter 9) - Scribal Correction and Literary Craft
Biblical illumination
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Portraiture and Presence in the Helmarshausen Psalter
The Leningrad Codex - The BAS Library
Making books for profit in medieval times
Interviews With the Authors: Myths and Mistakes—Zachary J. Cole
13.6.4: Books in Medieval Europe - Humanities LibreTexts
Full article: Manuscript Evidence of the Genesis of Sermons by Peter of Zittau
PAPYRUS 66 (P66): One of the Earliest Available Papyri - Christian Publishing House Blog