1. A. Kumar and A. Singh, Inter. J. Res. Pharm. and Biomed. Sci. 3, 534 (2012).
2. E. F. Gilman, Hibiscus rosa-sinesis, Fact Sheet FPS-254 (Cooperative Extension Service Institute of Food and Agricultural Sciences University of Florida, Florida, 1999).
3. M. H. Wijayakusuma, Tumbuhan Berkhasiat Obat Indonesia Jilid I (Gema Insani, Jakarta, 2000).
4. L. Beers and J. Howie, Growing Hibiscus (G. T. Setters Pty Limited, Hong Kong, 1990).
5. S. Hajar, B. Sc. Final Project, Universitas Indonesia, Depok, 2011.