1. S. Roysommuti, A. Suwanich, D. Jirakulsomchok, et al., Adv. Exp. Med. Biol., 13, (2009).
2. Y. J. Xu, A. S. Arneja, P. S. Tappia, et al., Exp. Clin. Cardiol., 13(2), 57 – 65 (2008).
3. United States Pharmacopeia 26, USP Convention Inc., Rockville (2003).
4. Japanese Pharmacopoeia 15, The National Institute of Health Sciences (2007).
5. Z. Chen, G. Xu, K. Specht, et al., Anal. Chim. Acta, 296(3), 249 – 253 (1994).