Peters, K., Peters, E.-M., Adam, W., Ahrweiler, M., & Reinhardt, D. (1998). Crystal structure of 13-acetyl-4,13-dimethyl-12-oxacyclopropane-12- spiro-2,4,6- triazatricyclo[5.2.2.02,6]undec-10-ene-3,5,9-trione, C13H13N3O5. Zeitschrift für Kristallographie - New Crystal Structures, 213, 311-312.