1. 19. Oran W. A. , to be published.
2. 21. Elleman D. D. , Private Communication; see also paper in poster session by W. K. Rhim, M. Saffren, and D. D. Elleman.
3. 24. Nordine P. C. and Atkins R. M. , to be published in RSI.
4. 14. Gammell P. , Private Communication.