title: Radiometric assays using labels of unknown specific activity: a method that overcomes efficiency problems.
mesh_terms: D002250:Carbon Radioisotopes; D005069:Evaluation Studies as Topic; D007553:Isotope Labeling; D008433:Mathematics; D008722:Methods; D011868:Radioisotopes; D011874:Radiometry; D014443:Tyrosine
chemical_list: D002250:Carbon Radioisotopes; D011868:Radioisotopes; D014443:Tyrosine