LITERATURE CITED
- Ainsworth, G. C. 1971. Ainsworth & Bisby's Dictionary of the Fungi (6th edition). Commonwealth Mycological Institute, Kew, Surrey. 663 p.
- Farrar, J. F. 1976. The lichen as an ecosystem: Observation and experiment. Pp. 385–406. In: Lichenology: Progress and problems. Eds., D. H. Brown, D. L. Hawksworth and R. H. Bailey. Academic Press, London and New York.
- Farrar, J. F. 1978. Symbiosis between algae and fungi. In: Handbook of nutrition and food. CRC Press.
- Hale, M. E. 1967. The biology of lichens. Edward Arnold, London. 176 p.
- Smith, A. L. 1921. Lichens. Cambridge University Press. 158 p.
- Stewart, W. D. P., and P. Rowell. 1977. Modifications of nitrogen-fixing algae in lichen symbioses. Nature 265: 371–372.