1. B. M. Levitin, Levulinic Acid, its Properties, Production, and Use [in Russian], ONT i TÉI Mikrobioprom [Division of Scientific, Technical, and Economic Information of the Microbiological Industry], No. 3, Moscow (1976).
2. A. A. Efremov, G. G. Pervishena, and B. N. Kuznetsov, Khim. Prir. Soedin., 107 (1997).
3. V. Carlusis and L. J. Torres, US Patent No. 3267136 (1996).
4. G. A. Slashchinin and A. A. Efremov, Khim. Drev., No. 6, 72 (1991).
5. A. A. Efremov, G. A. Slashchinin, E. D. Korniets, and B. N. Kuznetsov, RF Patent No. 1817770 (1992);