1. C. W. Chang, in “Responses of Plants to Air Pollution”,J. B. Mudd, T. T. Kozlowski, eds., Academic Press, New York, 1975, p. 57.
2. T. W. Goodwin, “The Biochemistry of the Carotenoids, Vol. 1, Plants”, Chapman and Hall, London, 1980.
3. M. Treshow, F. K. Andersen, “Plant Stress from Air Pollution”, John Wiley and Sons, Chichester, 1989.
4. B. H. Davies, in “Chemistry and Biochemistry of Plant Pigments, Vol. 2”,T. W. Goodwin, ed., Academic Press, New York, 1976, p. 38.
5. M. Holden, in “Chemistry and Biochemistry of Plant Pigments, Vol. 2”,T. W. Goodwin, ed., Academic Press, New York, 1976, p. 1.