Toward the chemical ecology of medicinal plant use in chimpanzees: The case of Vernonia amygdalina, a plant used by wild chimpanzees possibly for parasite-related diseases - Ohigashi, H; Huffman, M A; Izutsu, D; Koshimizu, K; Kawanaka, M; Sugiyama, H; Kirby, G C; Warhurst, D C; Allen, D; Wright, C W; Phillipson, J D; Timmon-David, P; Delmas, F; Elias, R; Balansard, G (J Chem Ecol, 1994)