Clean Synthesis of 1,8-Dioxo-octahydroxanthene Derivatives Catalyzed by p-Dodecylbenezenesulfonic Acid in Aqueous Media - Jin, Tong-Shou; Zhang, Jian-She; Xiao, Jin-Chong; Wang, Ai-Qing; Li, Tong-Shuang (Synlett, 2004)