9 [ measurement devices; namely, certified samples of materials, to be used in the calibration of measuring instruments; namely, metals, alloys, chemicals, minerals, fertilizers, botanicals, gases, biologicals, carbides, glasses, cements, trace elements, radioactive materials; namely, plutonium, uranium, thorium, cesium, americium, radium, europium and molybdenum, isotopics, reference fuels, rubber materials, computer tapes used for measurement, calibration and specific determination of the composition of said materials ]