1. G. W. Sanderson, “Recent Advances in Phyto-chemistry,” No. 5, ed. by V. C. Runeckles and T. C. Tso, Phytochemical Society of North America, 1972, p. 247.
2. G. Avigad, in “Plant Carbohydrates I, Intracellular Carbohydrates, Encyclopedia of Plant Physiology, New Series,” Vol. 13A, ed. by F. A. Loewus and W. Tanner, Springer-Verlag, Berlin, 1982, p. 278.
3. O. Kandler and H. Hopf, in “The Biochemistry of Plants,” ed. by J. Preiss, Vol. 3, Academic Press, London, 1980, p. 221.