P.  Kumar, Deshmukh, A. N., Upadhyay, R. K., and Gurjar, M. K., ?Simple and practical approach to enantiomerically pure (S)-3-hydroxy-gamma-butyrolactone: synthesis of (R)-4-cyano-3-hydroxybutyric acid ethyl ester?, Tetrahedron-Symmetry, vol. 16, no. 16, pp. 2717-2721, 2005.