Koch, M. A., Schuffenhauer, A., Scheck, M., Wetzel, S., Casaulta, M., Odermatt, A., Ertl, P., & Waldmann, H. (2005). Charting biologically relevant chemical space: A structural classification of natural products (SCONP). Proceedings of the National Academy of Sciences of the United States of America, 102(48):, pp. 17272-17277. Retrieved from http://dx.doi.org/10.1073/pnas.0503647102.