Mapping of structured documents 
Revision log
| Date | Revision description |
| 2023-04-25 | Introduced 'short-form' list of member Classes. |
| 2023-04-13 | Added code for defining information content of a class or document |
| 2022-11-03 | Simplified, removed references to TIPs, update graph |
| 2017-09-12 | Extended |
| 2017-08-25 | otally rewritten, still work in progress |
| 2014-10-16 | First issue |