Epoch

Check the 'Source' instruction to be sure that you are looking at the correct source(s) of information on the resource
If data on the resource and data as the element in the record are:
- PoR/PaE–check the Data Entry instructions:
  - data for this element must be Recorded as instructed: make sure the data is recorded as instructed
- PoR/AaE–check the Core instructions:
  - data for this element is NotCore:
    - if the data has been given as a wrong element, move it to the correct element
    - if the data is missing completely, add the data if you feel it might be useful–remember the principles of differentiation and sufficiency
- AoR/PaE–check the Source instructions again:
  - since this type of data is supposed to come from a specified source, or sources, on the resource itself (see the Source instructions above), if you cannot find the data on one of those sources, either delete the data or move it to another element, e.g., an appropriate note
- AoR/AaE–go to the next element:
  - but be sure to check the resource carefully, if the data for the element is Core, or if the data is important for differentiating the resource from a similar resource
Check below, for any useful Notes