Hextilda fitz Andlaw - Sources?

Hextilda fitz Andlaw has been added as the mother of Bethóc ingen Domnaill. However, Cawley's Medlands is clear that Donald Bane's wife's (and Bethoc's mother)'s name is not known.

The Hextilda profile says it was updated from WikiTree Genealogy by SmartCopy: Dec 12 2014, 14:05:49 UTC - Are there sources anyone can find to validate this profile?

As none supplied, I'm deleting this connection.