1. Castenholz, R. W., Bact. Rev., 33, 476 (1969).
2. Brock, T. D., Phycologia, 8, 201 (1969).
3. Van Baalen, C., J. Phyco., 3, 154 (1967).
4. Sistrom, W. R., and Clayton, R. K., Biochim. Biophys. Acta, 88, 61 (1964).
5. Olson, J. M., and Stanton, E. K., in The Chlorophylls (edit. by Vernon, L. P., and Seely, G. R.), 381 (Academic Press, New York, 1966).