Purba, Hermawan, et al. “Phytochemical Screening of Bunga Rosella (Hibiscus Sabdariffa L) and Antimicrobial Activity Test”. Jurnal Pendidikan Kimia, vol. 12, no. 2, Aug. 2020, pp. 70-78, doi:10.24114/jpkim.v12i2.19398.