1. C. Darwin , The Origin of Species by Means of Natural Selection, John Murray, London, 6th edn, 1872
2. D. Spiteller , Plant Defense Strategies in Encyclopedia of Ecology, ed. S. E. Jørgensen and B. D. Fath, Elsevier, Oxford, 2008, vol. 4, pp. 2798−2811
3. Chemical Defence Strategies of Higher Fungi
4. 5300 years ago, the Ice Man used natural laxatives and antibiotics
5. Laxatives and the Ice Man