Higuchi's fractal dimension for analysis of the effect of external periodic stressor on electrical oscillations in the brain. - Hiie Hinrikus; Maie Bachmann; Deniss Karai; Wlodzimierz Klonowski; Jaanus Lass; Pavel Stepien; Robert Stepien; Viiu Tuulik (Medical Biol. Eng. Comput., 2011)