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[8] A. H. Mekler, Finitely additive measures on N and the additive property, Porc. Amer. Math. Soc. 92 (1984), 439-444. Department of Mathematical Science, Graduate School of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan E-mail address: tk-waseda@ruri.waseda.jp