Herbert Thurston, S.J., "The Origin of the Scapular – A Criticism."The Irish Ecclesiastical Record Vol XVI July–December 1904. pp. 59–75. Dublin: Browne & Nolan, Limited. – well researched 1904 journal article demonstrates the falsity of the Swanington letter as well as the forged papal bull that was the basis of the "Sabbatine privilege", discusses Carmelite history and the facts about the evolution of the scapular devotion etc.
Carmel, Its History, Spirit, and Saints. New York: P.J. Kennedy & Sons, 1927. pp 218–226. The Brown Scapular – Book excerpt found at the web link contains extensive quotes from the 17th century forged letter purportedly written in the 13th century by Simon Stock's secretary "Peter Swanington". Many older sources surprisingly accepted the Swanington letter without question.
