10. Dawson, R. F., R. D. Carpenter, F. L, Gager, Jr., R. W. Jenkins, Jr., and R. H. Newman: Proc. International Tob. Sci. Congress, 5th, Hamburg, Sept. 1.4-1.9, 1.970, pp. 245-250 (1971); Tob. Abstr. 16 (1.972), p. 965, Abstr, 2366,
18. Katz, M., and 5. Halpem: Ind. Eng. Chem. -·42 (1950) 345· 'l9· Jenkins, R. W., Jr., and R. T. Bass: The preparation of carbon-14 labeled cigarettes (Philip Morris Research Center); 27th Tobacco Chemists' Res. Conf., Oct. 3-5, 1.973, Winston-Salem, N. C.
21. Winston, P. W., and D. H. Bates: Ecology 41. (1.960) 2J2. 22, Wilson, C. L., and D. W. Wilson: _C9mprehensive analytical <hemistry, Vol. 1.A, p. 361; Elsevier, N. Y., 1.959.