Reference Data - overview 
Revision log
| Date | Revision description |
| 2022-10-19 | Updated the counts |
| 2019-11-06 | Updated the counts |
| 2018-12-22 | Updated the counts |
| 2018-10-30 | Updated the counts |
| 2018-01-14 | Updated the counts |
| 2017-06-19 | Made corrections to reflect agreed-upon changes in the semantics of ClassOfFunctionalObject; added a list of RDL extensions |
| 2016-09-11 | Added link to RDL2 (the working copy of the RDL) |
| 2015-12-13 | After discussions left out all ISO 15926-4 XXXXX as superclasses. |
| 2015-08-30 | Updated the site map |
| 2015-07-12 | First issue |