A. Basile, K. P. S. Bhaskara Rao, Completeness of Lp-Spaces in the Finitely Additive Setting and Related Stories, J. Math. Anal. Appl. 248, (2000) 588-624.
 W. C. Bell, J. W. Hagood, Completeness of Lp spaces and Radon-Nikodym theorems for unbounded finitely additive measures, J. Math. Anal. Appl. 218 (1998) 82-96.
 K. P. S. Bhaskara Rao, M. Bhaskara Rao, Theory of charges, Academic Press, London, 1983.
 A. Blass, R. Frankiewicz, G. Plebanek, C. Ryll-Nardzewski, A note on extensions of asymptotic density, Proc. Amer. Math. Soc. 129 (11) (2001) 3313-3320.
 M. Blu¨mlinger, Levy group action and invariant measures on βN, Trans. Amer. Math. Soc. 348 (12) (1996) 5087-5111.
 R. C. Buck, The measure theoretic approach to density, Amer. J. Math. 68 (1946) 560-580.
 C. Chou, Minimal sets and ergodic measures for βN \ N, Illinois J. Math. 13 (1969) 777-788.
 P. Letavaj, L. Miˇs´ık, M. Sleziak, Extreme points of the set of density measures, J. Math. Anal. Appl. 423 (2015) 1150-1165.
 D. Maharam, Finitely additive measures on the integers, Sankhya Ser. A 38 (1976) 44-59.
 A. H. Mekler, Finitely additive measures on N and the additive property, Porc. Amer. Math. Soc. 92 (1984) 439-444.
 R. R. Phelps, Lectures on Choquet's Theorem, 2nd ed., Springer-Verlag, Berlin, 2001.
 M. Sleziak, L`evy group and density measures, J. Number Theory 128 (12) (2008) 3005-3012.
 J. Tanaka, Flows in fibers, Trans. Amer. Math. Soc. 343, (1994) 779-804.
 E. K. van Douwen, Finitely additive measures on N, Topology Appl. 47 (1992) 223-268.
 J. de Vries, Elements of Topological dynamics, Kluwer Academic Publishers, Dordrecht, 1993. Department of Mathematical Science, Graduate School of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan E-mail address: firstname.lastname@example.org