1. The evolution of iron gall ink and its aesthetical consequences;James,2001
2. An indicator of its time: two millennia of the iron–gall-nut test;Edmonds;Analyst,1998
3. Naturalis Historiae, Book 34, p. 112;Plinius Secundus,1995
4. Theophilus: The Various Arts;Dodwell,1961
5. A physical perspective of Codex Sinaiticus: an overview from British Library;Moorhead,2015