Analisis perlakuan pajak penghasilan atas penjualan konten Ring Back Tone (RBT) antara Perusahaan Operator (Provider) dengan Partner: studi kasus PT XYZ = Analysis of the income tax treatment on sale of content Ring Back Tone (RBT) between the Company Operator (Provider) and Partner: case study PT XYZ - Eliana Eka Kurniawati, author (2012)