Strack, D., Schmitt, D., Reznik, H., Boland, W., Grotjahn, L., & Wray, V. (1987). Humilixanthin, a new betaxanthin from Rivina humilis. Phytochemistry, 26(8), 2285-2287. doi:10.1016/S0031-9422(00)84702-0.