[1,2-13C2]-4-Aminobutyric acid

[2-13C]-4-Aminobutyric acid

[13C,15N2]-Gemcitabine triphosphate

[13C6]-8-(4-Chlorophenylthio)-2＇-O-methyladenosine 3＇,5＇-(acetyloxy)methyl)-cyclic monophosphate