1. C. M. Pio, Dicionorio de Plantas Medicinais Uteis do Brasil e das Exoticas Cultivadas, Ministerio da Agricultura: Rio de Janeiro, Brazil, 1931, vol. II, p. 363.
2. T. B. Lee, Illustrated flora of Korea, Hwang Mun Sa: Seoul, 1982, Korea, p. 613.
3. A. F. Costa, Farmacognosia, 2nd ed. Lisboa, Fundacao Calouste Gulbenkian, 1968, vol. 1, p737.
4. V. Vardar and S. S. Oflas, Qual. Plant. Mater. Veg., 22, 145 (1973).
5. K. Yoshikawa, H. Hirai, M. Tanaka, and S. Arihara, Chem. Pharm. Bull., 48, 1093 (2000).