1. Virtanen and Laine, Suomen Kemistilehti, B, 9, 5 and 12 (1936); cf. the reviews by Burris and Wilson in Ann. Rev. Biochem., 14, 685 (1945); Wilson and Burris in Bact. Rev., 11, 41 (1947); and Virtanen, Biol. Rev., 22, 239 (1947).
2. Roine, Ann. Acad. Sci. Fenn.t, Ser. A. II, Chem. No. 26 (1947).
3. Blom, Ber., 59, 121 (1926).
4. Csáky, T. Z., Acta Chem. Scand. (in the press).