1. Moran, J. M., Crowther, P. P., Burke, B. F., Barrett, A. H., Rogers, A. E. E., Ball, J. A., Carter, J. C., and Bare, C. C., Science, 157, 676 (1967).
2. Bare, C. C., Clark, B. G., Kellermann, K. I., Cohen, M., and Jauncey, D. L., Science, 157, 189 (1967).
3. Broten, N. W., Locke, J. L., Legg, T. H., McLeish, R. S., Richards, R. M., Chisholm, R. M., Gush, H. P., Yen, J. L., and Galt, J. A., Science, 156, 1592 (1967).
4. See, for example, Bohr, Niels, Atomic Physics and Human Knowledge, 32 (Science Editions, New York, 1961).
5. Serber, R., and Townes, C. H., Quantum Electronics, (edit. by Townes, C. H.), 233 (Columbia University Press, New York, 1960).