title: [Radioactive and radiation standards. (IX), 7. Standard sources for environmental radioactivity measurement: (2) Unsealed radioactivity calibration samples (author's transl)].
mesh_terms: D000398:Air Pollution, Radioactive / Q000032:analysis*; D003037:Cobalt Radioisotopes / Q000032:analysis; D011005:Plutonium / Q000032:analysis; D011834:Radiation Monitoring / Q000592:standards*; D012015:Reference Standards; D013326:Strontium Radioisotopes / Q000032:analysis; D014878:Water Pollution, Radioactive / Q000032:analysis*
chemical_list: D003037:Cobalt Radioisotopes; D013326:Strontium Radioisotopes; D011005:Plutonium