1. Marsh, F. verbal suggestion to J. S., 1972
2. Wendelbo, Ø. personal communication to J. S., 10 April, 1972
3. Wendelbo, Ø.op. cit.
4. Wendelbo, Ø. The use of proteolytic enzymes in the restoration of paper and papyrus [D. Med. thesis] Bergen, 1977, conclusion, p. 3
5. Protein »Surgery«. A Restoring Procedure Applied on Paper