Succinyl Anhydride-13C4;2,5-Diketotetrahydrofuran-13C4;Tetrahydro-2,5-furandione-13C4;U-(13)C-succinic anhydride;Tetrahydro-2,5-dioxofuran-13C4;Succinic Acid Anhydride-13C4;Rikacid SA-13C4;Dihydro-2,5-furandione-13C4;succinic anhydride-(13)C4;13C4-succinic anhydride;Butanedioic Anhydride-13C4;Succinyl Oxide-13C4