http://books.google.com/books?id=uDsJAAAAIAAJ&pg=PA390 - Dictionary of National Biography (1900 edition), which attributes "Darby and Joan" to Henry Woodfall. Under "Woodfall, Henry Sampson (1739-1805): His father, Henry Woodfall, was printer of the 'Public Advertiser' in Paternoster Row, and master of the Stationers' Company in 1766, while at his death in 1769 he was a common councilman of many years' standing. He had been apprenticed to John Darby (d. 1730) of Bartholomew Close in 1701, and Darby and his wife were the subjects of his ballad, 'Darby and Joan' (first printed in 'Gentleman's Magazine' for March 1735, p. 153, under the heading 'The Joys of Love never forgot. A Song')."