The Authenticity of the Z-Text of Piers Plowman: Further Notes on Metrical Evidence.
Schmidt’s “transitional type” (a line with a post-caesural stave that repeats the alliterative sound of the a-verse but without stress and which has two staves bearing stress and alliterating bb at the end) occurs far more frequently in WL’s verse than elsewhere in the tradition, and is authorial. All eleven instances of T-type lines found elsewhere in a corpus of 12,806 lines (fifteen poems) are either certainly or most probably scribal errors, whereas two and quite possibly three lines of the Z text are authentic T-types; given the relative infrequency of T-type lines in PPl, this is significant. Moreover, only PPl, PPCreed, and the Z text have authentic lines in which both initial and medial dips contain two or more syllables.
MAE 56 (1987): 25-45.
Duggan, Hoyt N.