Wagnalls, New York, 1967 The Northern Wars, 1558-1721 by Robert I. Frost; Longman, Harlow, England; 2000 Norges festninger by Guthorm Kavli; Universitetsforlaget; 1987; Admiral Thunderbolt by Hans Christian Adamson, Chilton Company, 1958 East Norway and its Frontier by Frank Noel Stagg, George Allen & Unwin, Ltd. 1956 External links Great Northern War Timeline Great Northern War Forts in Norway Wars involving Norway Wars involving Denmark Wars involving Russia Northern War and Norway, Great 18th century in Norway