Binaural entrainment of 2000-2040 Hz and 2000-2090 Hz increase Glial Fibrillary Acidic Protein (GFAP) expression of astrocytes in the CA1 rat hippocampus during operant learning conditioning - Nugraha, Zainuri Sabta (Journal of the Medical Sciences (Berkala ilmu Kedokteran), 2015)