1. GUTENBERG'S INKS AND PAPERS: NON-DESTRUCTIVE COMPOSITIONAL ANALYSES BY PROTON MILLIPROBE
2. Forty Centuries of Ink;Carvalho,1904
3. Cyclotron Analysis of the Ink in the 42-Line Bible
4. R.A. Eldred, B.H. Kusko and T.A. Cahill, these Proceedings (PIXE-83), p. 579.
5. R.N. Schwab, T.A. Cahill, B.H. Kusko and R.A. Eldred, submitted to the Gutenberg Jahrbuch, ed., A.L. Ruppel (Gutenberg-Gesellschaft, Mainz).