Magna Britannica et Hibernia.Volume 6: Westmorland by Thomas Cox (Vicar of Bromfield, Essex) 45 pages, printed in 1731.
Transcription by Sarah Reveley, Joan Fisher and Lisl Schoenwald.
"Merton, and Mertone, the Lordship of Thomas Holland, Earl of Kent, who dying possessed of it, and leaving Joan his Wife, who had been parted from William de Montacute, Earl of Salisbury, surviving, she had allotted her, as Part of her Dowry, this Manor and divers other Estates. She within a Year married to Edward, Prince of Wales, commonly called the Black Prince, and held it to the ninth Year of King Rich. II. which was twenty one Years from her Husband 's Death; she died that Year, and it passed to her Son Thomas Holland, Earl of Kent; but how, or when he alienated it, it doth not appear; yet four Years after, we find Roger Lord Clifford 4th died possessed of it, and left it to his Son Thomas, and his Heirs, with other Estates. Brampton, the Lordship of Roger Lord Clifford, who died possessed of it"
The Later Records relating to North Westmorland by John F. Curwen (1932) on British History Online
Cumbria County History Trust has published a "Jubilee Digest" for the township of Long Marton