Callacondo-Riva D, Quispe-Mauricio A, Lindo-Gamarra S, Vaisberg AJ. Cytotoxic activity of an ethanolic extract of Gnaphalium spicatum "keto keto" on human tumor cell lines. Rev Peru Med Exp Salud Publica. 2008;25(4). doi:10.17843/rpmesp.2008.254.1301