1. Adler, E.: Acta Chem. Scand. 2, 93 (1948), p. 60, 72, 74.
2. Adler, E.: Paperija Puu 43, 634 (1961), p. 74.
3. Adler, E.: Advances in Chem. Ser. 59, IX (1966), p. 50, 52.
4. Adler, E., B. Becker, T. Ishihara und A. Stanwix: Holzforschung 20, 3 (1966); here, earlier literature dealing with hydroxyl and carbonyl distribution in lignin is quoted, p. 60, 72, 73.
5. Adler, E., and L. Ellmer: Acta Chem. Scand. 2, 839 (1948), p. 60, 72, 74.