MIL-S-7998A (AMENDMENT 1), MILITARY SPECIFICATION: SANDWICH CONSTRUCTION CORE MATERIAL, BALSA WOOD (13 FEB 1978) [NO S/S DOCUMENT]., This amendment forms a part of MilitarySpecification MIL-S-7998A, dated6 March 1970, and is approved for useby al1 Departments and Agencies of theDepartment of Defense.