Label: beating stones

Roberts, Matt, Don Etherington, and Margaret R. Brown. 1982. Bookbinding and the conservation of books: a dictionary of descriptive terminology. Washington: Library of Congress.

Jeffrey S. Peachey (2013), "Beating, rolling, and pressing : the compression of signatures in bookbinding prior to sewing", in Suave mechanicals: essays on the history of bookbinding, Ann Arbor (MI), The Legacy Press, pp. 317-381.