Declercq, J.-P., Germain, G., Vanmeerssche, M., Greenhill, JV., Chaaban, I., & Dekimpe, N. (1981). 2-[3,3,5′,5′,6,6,-hexamethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroxanthen-9-spirocyclohex-2′-en-3′-yl]-3-hydroxy-5,5-dimethylcyclohex-2-enone,C32h42o5. Crystal Structure Communications, 10(4), 1335-1340. https://hdl.handle.net/2078.5/144790 (Original work published 1981)