 Complete the following phrase:  The earliest known reference to a board shear comes from an 1842 supplement to Penny Magazine, titled A Day at a Bookbinders, which included a drawing of a board shear with many of the major developments already present. An 1854 article on the history of bookbinding from The Bookbinders Trade Circular describes early board shears, and places their development in about 1836; credit for the invention is ascribed to Warren De La Rue in the Reports of the Juries from the 