1. Kertesz, Z.I.: The Pectic Substances, Interscience Publishers, Inc. New York (1951)
2. Hultine, H.O., Levine, A.S.: Arch. Biochem. Biophysics 101, 396 (1963)
3. Pieper, H.J., Oplustil, E.: 5th Internat. Fermentat. Symp., Berlin (1976) Abstracts of Papers, p. 374 Verlag Versuchs-u. Lehranstalt f. Spiritusfabrik. u. Fermentations-technologie, Berlin
4. Hall, C.G.: Nature (London), 12, 717 (1966)
5. Pollard, A., Kieser,M., Sissons, D.J. : Chem. and Ind. 36, 952 (1958)