1. https://clinicaltrials.gov/ct2/results?term=QS-21&Search=Search .
2. Ragupathi G, Gardner JR, Livingston PO, Gin DY (2011) Natural and synthetic saponin adjuvant QS-21 for vaccines against cancer. Expert Rev Vaccines 10:463–470
3. Dalsgaard (1978) A study of the isolation and characterization of the saponin Quil-A®. Evaluation of its adjuvant activity, with a special reference to the application in the vaccination of cattle against foot-and-mouth disease. Acta Vet Scand Suppl 69:7–40
4. Kensil CR, Patel U, Lennick M, Marciani D (1991) Separation and characterization of saponins with adjuvant activity from Quillaja Saponaria Molina cortex. J Immunol 146:431–437
5. http://www.ema.europa.eu/ema/index.jsp?curl=pages/news_and_events/news/2015/07/news_detail_002376.jsp&mid=WC0b01ac058004d5c1 .