external sewing supports

Source reference: 

Pickwoad, The use of fragments... (2000)

Nicholas Pickwoad (2000), “The Use of Fragments of Medieval Manuscripts in the Construction and Covering of Bindings on Printed Books”, in Interpreting and Collecting Fragments of Medieval Books, edited by Linda L. Brownrigg and Margaret M. Smith, Seminar in the History of the Book to 1500. Conference (7th : 1998 : Oxford), Los Altos Hills (CA); London: Anderson-Lovelace ; Red Gull Press, pp. 1–20.

Additional reference: 
p. 8

Used as preferred label for