1-(2-Deoxy-β-D-erythro-pentofuranosyl)-5-methyl-2,4(1H,3H)-pyrimidinedione-1',2',3',4',5'-13C5; 1-(2-deoxy-β-D-erythro-pentofuranosyl)-5-methyl-2,4(1H,3H)-Pyrimidinedione-1',2',3',4',5'-13C5; 2'-Deoxythymidine-3'-13C; 5-Methyl-2'-deoxyuridine-1',2',3',4',5'-13C5; 5-Methyldeoxyuridine-1',2',3',4',5'-13C5; DThyd-1',2',3',4',5'-13C5; Deoxyribothymidine-1',2',3',4',5'-13C5; Deoxythymidine-1',2',3',4',5'-13C5; NSC 21548-1',2',3',4',5'-13C5; Thymidin-1',2',3',4',5'-13C5; Thymine 2-Desoxyriboside-1',2',3',4',5'-13C5; Thymine Deoxyriboside-1',2',3',4',5'-13C5; 2'-Deoxy-5-methyl-uridine-1',2',3',4',5'-13C5; dT-1',2',3',4',5'-13C5; Thymine-1,2-deoxy-β-D-ribofuranoside-1',2',3',4',5'-13C5;