Some organisations, such as https://www.iceservices.com, need writer agreement references for controlled writers in CWRs to accept work registrations. After speaking to ICE, I've learned that this should go into the PWR record of the CWR.

I suggest implementing the field on the ownership section of the rights tab on individual work similar to the agreement reference .

The alternative would maybe be to have a field for it on a songwriter level. However that would be an issue in cases where a publisher has multiple agreements with the same songwriter. So if you for some reason would prefer this, the field should allow multiple entries and there should be a select menu on the work level for choosing the relevant agreement number for the specific work.

Feel free to reach out to me if you have questions or need to discuss something related to this.

Best,