1. K. Freudenberg, Science, 1965, 148, 595.
2. K. Freudenberg, Holzforschung, 1964, 18, 3.
3. V. M. Reznikov, Khimiya drevesiny [Wood Chemistry], 1977, 3, 3 (in Russian).
4. Yu. I. Khol’kin, Tekhnologiya gidroliznykh proizvodstv [Hydrolysis Production Technology], Lesn. prom-st’, Moscow, 1989, 233 pp. (in Russian).
5. T. N. Spirina, N. N. Saprykina, O. A. Andreeva, Zh. Prikl. Khim., 2012, 85, 794 [Russ. J. Appl. Chem. (Engl. Transl.), 2012, 85].