A. Manurung, A. H. Manurung, G. Manurung, L. H. Sangapan, G. Manurung, and J. M. Simanjuntak, “Free Cash Flow of Telecommunications Companies in Indonesia”, Jurnal Ekonomi dan Bisnis Jagaditha, vol. 12, no. 2, pp. 258–268, Sep. 2025.