modificationRecord — To associate a reference single letter with a modification event
modificationRecord :  modID,  [refID]
     (author, description?, extraDocRef*)
| modID - a single letter used to identify all modified data with this mod | 
| refID (optional) - an optional document reference for this modification | 
A modificationRecord associates a single letter (such as modification "A") with a modification author, address, and any optional external reference documents, in keeping with the AIAA draft standard.
| fileHeader | 
| author | 
| description | 
| extraDocRef |