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2. U.S. Public Health Service: 1969, Air Quality Criteria for Particulate Matter, NAPCA Publ. No. AP-49 U.S. Government Printing Office.
3. Junge, C. E.: 1963, Air Chemistry and Radioactivity, Academic Press, N.Y., p. 228.
4. Lamb, H.H. and Johnson, A. I.: 1959, Geogr. Annaler 41, 94-134; 1961, ibid. 43, 363–400.
5. Mitchell, Jr., J. M.: 1965, in The Quaternary of the United States (ed. by H. E. Wright and D. G. Frey), Princeton University Press, pp. 881–901. Mitchell, Jr., J. M.: 1967, in Encyclopedia of Atmospheric Sciences and Astrogeology (ed. by R. W. Fairbridge ), Reinhold Publ. Co., pp. 211–213.