D. Popivanov S. Jivkova V. Stomonyakov G. Nicolova Effect of independent component analysis on multifractality of EEG during visual-motor task. 2112-2123 2005 85 Signal Processing 11 http://dx.doi.org/10.1016/j.sigpro.2005.07.005 db/journals/sigpro/sigpro85.html#PopivanovJSN05