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Johnson, E.L.; Schmidt, W.F.; Norman, H.A., Flavonoids as markers for Erythroxylum Taxa: E. coca var. ipadu and E. novogranatense var. truxillense, Biochem. Syst. Ecol., 1998, 26, 7, 743-759, https://doi.org/10.1016/S0305-1978(98)00042-8 . [all data]