368 . LIST ET AL. E. P. Hardy, Jr., R. J. List, L. Machta, L. T. Alexander, J. S. Allen, and M. W. Meyer, Strontium-90 on the Earth’s Surface II, USAEC Report TID17090, November 1962, . E. P. Hardy, Jr., and Joseph Rivera, in Fallout Program Quarterly Summary Report, USAEC Report HASL~149, pp. 29-42, Health and Safety Laboratory, Oct. 1, 1964, E. P. Hardy, Jr., Vertical Penetration of Sr in Three Soils Sampled in March 1963, in Fallout Program Quarterly Summary Report, USAEC Report HASL-138, pp. 249-250, Health and Safety Laboratory, July 1, 1963. L. T. Alexander, J.S. Allen, and E, P. Hardy, Jr., Strontium-90 in Soils Collected in 1962, in Fallout Program Quarterly Summary Report, USAEC Report HASL~142, pp. 293-296, Health and Safety Laboratory, Jan. 1, 1964. H. H. Hanks, Jr., M. J. Long, and R. G. Beebe, Tropopause Penetration by Cumulonimbus Clouds, Report AFCRL-64-111, Air Force Cambridge Research Laboratories, February 1964.