Crystal structure of dimethyl (1α,2β,3α,4β,7β,8α,9β,10α)-13-isopropylidene- pentacyclo[8.2.1.14,7.02,9.03,8]tetradeca-5,11-diene-2,9-dicarboxylate, C21H24O4 - Russell R. A.; Schultz A. C.; Warrener R. N.; Tiekink R. T. (Zeitschrift für Kristallographie - New Crystal Structures, 2002)