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2. A. I. Tikhomirov, Izv. Vsesoyuz. Geogr. Ob-va 91, No. 5, 424 (1959).
3. A. I. Tikhomirov, Izv. Vsesoyuz. Geogr. Ob-va 95, No. 2, 134 (1963).
4. G. K. Rodgers, in Proc. of the 11th Intern. Conf. on Great Lakes Res., Wisconsin, Apr. 18–20, 1968, p. 942.
5. D. W. Hubbard and I. D. Spain, in Proc. of the 16th Conf. on Great Lakes Research, Ann Arbor (Michigan, 1973), p. 735.