The Relationship of the Vernon and Clopton Manuscripts.
PPl was originally bound in the Clopton manuscript with a text of Mandeville’s Travels (Defective Version) as it was included in four other manuscripts, including one, Harley 3954, which is otherwise composed of religious works.
Pearsall, Studies in the Vernon Manuscript. 29-44, esp. 30, 35, 40-41.