See Chapter 18, Legends and Tales, and section The Castle Ghost, page 207 which also recounts the article in 1962 by Patrick Denis O'Donnell in Ireland of the Welcomes.
Refer to Chapter 18 under Legends and Tales, specifically The Castle Ghost on page 207. This section also includes a recounting of the 1962 article written by Patrick Denis O'Donnell for Ireland of the Welcomes.