Tawfik, W. A., K. A. Shams, N. S. Abdel-Azim, N. M. Hassan, and S. I. Ismail. “NAPHTHAQUINONES OF ALKANNA ORIENTALIS (L.) BOISS”. African Journal of Traditional, Complementary and Alternative Medicines, vol. 4, no. 1, Aug. 2006, pp. 55-58, https://athmsi.org/journals/index.php/ajtcam/article/view/158.