Fluctuation in e-mail sizes weakens power-law correlations in e-mail flow Yoshitsugu Matsubara, Yasuhiro Hieida and Shin-ichi Tadaki Eur. Phys. J. B, 86 9 (2013) 371 Published online: 04 September 2013 DOI: 10.1140/epjb/e2013-40209-x