Richie, the Pettitt I was referring to was Tom Pettitt, who with Flemming G. Andersen in JAFL in 1979 totally swept the board with David Buchan's silly oral-formulaic composition theory using Mrs Brown's ballads.

Andersen's 'Commonplace and Creativity' is well worth getting hold of, dealing with what we more commonly here refer to as floating verses (commonplaces/formulaic poetry). This is an area that needs much more study in the Child Ballads. I personally think those sophisticated people who were making up and editing ballads in the 18th and early 19th centuries were passing these freely from one ballad to another in order to make their compositions/re-compositions look more traditional.