“RISIKO SISTEMATIS, FAKTOR INTERNAL DAN EKSTERNAL PERUSAHAAN TERAHADAP RETURN SAHAM”, bisnisekonomi, vol. 13, no. 1, hlm. 55–65, Apr 2015, Diakses: 1 November 2026. [Daring]. Tersedia pada: https://journal.unimma.ac.id/bisnisekonomi/article/view/134