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: the data must be appropriate for the resource, even if it is not entered exactly as instructed due to interpretation or error
- PoR/AaE–check the Core instructions:
  - data for this element is NotCore: if the data has not been given as another element instead:
    - it is ok if the element is missing, since the other cataloger might simply have decided not to add it; but
    - it is not ok if you feel that the fact that the element is missing indicates a true difference
- AoR/PaE–check the Source instructions again:
  - since this type of data is supposed to come from a specific source, it is not ok if the data cannot be found on that source (except for error or special instructions for the element)
- 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