[1] T. Alaste and M. Filali, slowly oscillating functions and closed left ideals of βS, Topology Appl. 156 (2009), 669–673.
[2] J.F. Berglund, H.D. Junghenn and P. Milnes, Analysis on Semigroups: Function Spaces, Compactifications, Representations, Wiley, New York, 1989.
[3] M. Filali and I. Protasov, Asymptotic oscillations, Topology Appl. 154 (2007), 561–566.
[4] M. Filali and P. Salmi, Slowly oscillating function in semigroup compactification and convolution algebra, J. Funct. Anal. 250 (2007), 144–166.
[5] N. Hindman and D. Strauss, Algebra in the Stone-Cech Compactification, Theory and Application ˘ , Springer Series in Computational Mathematics, Walter de Gruyter, Berlin, 2011.
[6] I. Protasov, Normal ball structures, Mat. Stud. 20 (2003), 3–16.
[7] I. Protasov, Metrizable ball structures, Algebra Discrete Math. 1 (2002), 129–141.
[8] J. Roe, Lectures on Coarse Geometry, no. 31, American Mathematical Soc., 2003.
[9] M.A. Tootkaboni, Lmc-compactification of a semitopological semigroup as a space of e-ultrafilters, New York J. Math. 19 (2013), 669–688.