Medium of Performance

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 from a vocabulary (Open): the term(s) must be appropriate for the resource, even if they are not from the official list of terms
- PoR/AaE–check the Core instructions:
  - data for this element is CoreIf: if the data has not been given as another element instead:
    - it is ok if the element is missing, as long as the related element is present or if the specific circumstances allow it to be skipped; but
    - it is not ok:
      - if the element is missing and the related element is also missing or if the specific circumstance do not allow it to be skipped (except for error or old cataloging rules); or
      - if you feel that the fact that the element is missing indicates a true difference
- AoR/PaE–check the Source instructions again:
  - since the Source for this element is or includes 'Any': accept the data, but only if it seems applicable
- 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