1. N. F. Efendieva, O. P. Grushnikov, and N. N. Shorygina, Abstracts of Papers Delivered at the Fifth All-Union Conference on Lignin Chemistry, Riga [in Russian], Zinatne (1971), p. 6.
2. N. N. Shorygina and N. F. Éfendieva, Izv. Akad. Nauk SSSR, Ser. Khim., 1393 (1973).
3. N. F. Éfendieva, N. M. Shorygina, and N. P. Krasovskaya, ibid., 2812 (1973).
4. E. Adler and J. Marton, Acta Chem. Scand.,15, 357 (1961).
5. J. Marton and E. Adler, ibid.,15, 370 (1961).