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Ulbricht C, Conquer J, Flanagan K, et al. (2013). "An Evidence-Based Systematic Review of Tongkat Ali (Eurycoma longifolia) by the Natural Standard Research Collaboration". Journal of Dietary Supplements. 10 (1): 54–83. doi:10.3109/19390211.2012.761467. PMID23419023. S2CID41416936.
Ang HH, Lee EL, Cheang HS (2004). "Determination of Mercury by Cold Vapor Atomic Absorption Spectrophotometer in Tongkat Ali Preparations Obtained in Malaysia". International Journal of Toxicology. 23 (1): 65–71. doi:10.1080/10915810490269654. PMID15162849. S2CID3062564.
Ulbricht C, Conquer J, Flanagan K, et al. (2013). "An Evidence-Based Systematic Review of Tongkat Ali (Eurycoma longifolia) by the Natural Standard Research Collaboration". Journal of Dietary Supplements. 10 (1): 54–83. doi:10.3109/19390211.2012.761467. PMID23419023. S2CID41416936.
Ang HH, Lee EL, Cheang HS (2004). "Determination of Mercury by Cold Vapor Atomic Absorption Spectrophotometer in Tongkat Ali Preparations Obtained in Malaysia". International Journal of Toxicology. 23 (1): 65–71. doi:10.1080/10915810490269654. PMID15162849. S2CID3062564.