John Burrow & Thorlac Turville-Petre 
Piers Plowman : The B-Version Archetype (Bx) [PDF ebook] 
The B-Version Archetype (Bx)

This edition, the first of its kind in
Piers Plowman studies, aims to establish the archetypal text of the B-version of the poem, the ancestor of all extant manuscripts. The editors claim that this can be determined with certainty in the majority of lines by examining the relationship between the best copies of the alpha and beta families of the B-version stemma. Past editors have attempted to reconstruct the authorial text by extensive emendation, but Burrow and Turville-Petre claim that the archetype was not nearly as corrupt as previously maintained. In
Piers Plowman: The B-Version Archetype the editors have opened a new chapter in the study of the B-text tradition.