(S)-Tetrahydro-5-oxo-2-furancarboxylic Acid(2S)-Tetrahydro-5-oxofuran-2-carboxylic Acid(S)-5-Oxo-2-tetrahydrofurancarboxylic Acid(S)-(+)-5-Oxo-2-tetrahydrofurancarboxylic Acid5S-(+)-Butyrolactone Carboxylic Acid(2S)-Tetrahydro-5-oxo-2-furancarboxylic Acid