incentive to devise ways of increasing a bridge's possible span, and the frequently used king-post design could only extend so far. Burr's design, which bolted a single arched timber to the king-post braces, added such stability that not only did the king-post trusses become secondary supports but also the bridge's possible reach greatly increased. See also List of covered bridges in Vermont References Congdon, Herbert Wheaton. The Covered Bridge. 4 ed. Middlebury: Vermont Books, 1973. Wagemann, Clara E. Covered Bridges of New England. Rutland: Charles E. Tuttle Co., 1952. Jakeman, Adelbert M. Old Covered Bridges: The Story of Covered Bridges in General. Brattleboro: Stephen Daye Press, 1935. Walker, C. Ernest. Covered Bridge Ramblings in New England. Contoocook: C. Ernest Walker, 1959. Hill, Ralph Nading and Lilian Baker Carlisle. The Story of the Shelburne Museum. 1955. External links Direct link to US Patent No. 2769 image Covered Bridge Covered bridges in Vermont Wooden bridges in Pennsylvania Road bridges in Vermont Pedestrian bridges in Vermont Former road bridges in the United States Relocated buildings and structures in Vermont Burr Truss bridges in the United States 1845 establishments in Vermont