3. A method according to claim 1 wherein said device is used to read a second physical paper identifier coding for said second electronic document and to communicate to said processor information enabling said identity of said second electronic document to be established.
3. A method according to claim 1 wherein said device is used to read a second physical paper identifier coding for said second electronic document and to communicate to said processor information enabling said identity of said second electronic document to be established. 4. A method according to claim 3 wherein said first physical paper identifier comprises a first sheet of digital paper having a device readable position-determining pattern and having human readable content; said second physical paper identifier comprises one or more sheets of digital paper having a device readable position-determining pattern.