The extract salaon (Indigofera tinctoria L) leaf as the natural dye of ulos in keeping for the batak culture values. J.Pendidik.Kim [Internet]. 2017 Aug. 31 [cited 2026 Apr. 30];9(2):293-8. Available from: https://jurnal.unimed.ac.id/2012/index.php/jpk/article/view/7602