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Gao H, Wu L, Kuroyanagi M, et al. (noviembre de 2003). «Antitumor-promoting constituents from Chaenomeles sinensis KOEHNE and their activities in JB6 mouse epidermal cells». Chemical & Pharmaceutical Bulletin51 (11): 1318-21. PMID14600382. doi:10.1248/cpb.51.1318.
Abe F, Yamauchi T, Nagao T, et al. (noviembre de 2002). «Ursolic acid as a trypanocidal constituent in rosemary». Biological & Pharmaceutical Bulletin25 (11): 1485-7. PMID12419966. doi:10.1248/bpb.25.1485.
Ji ZN, Ye WC, Liu GG, Hsiao WL (noviembre de 2002). «23-Hydroxybetulinic acid-mediated apoptosis is accompanied by decreases in bcl-2 expression and telomerase activity in HL-60 Cells». Life Sciences72 (1): 1-9. PMID12409140. doi:10.1016/S0024-3205(02)02176-8.
Pisha E, Chai H, Lee IS, et al. (octubre de 1995). «Discovery of betulinic acid as a selective inhibitor of human melanoma that functions by induction of apoptosis». Nature Medicine1 (10): 1046-51. PMID7489361. doi:10.1038/nm1095-1046.
Zuco V, Supino R, Righetti SC, et al. (enero de 2002). «Selective cytotoxicity of betulinic acid on tumor cell lines, but not on normal cells». Cancer Letters175 (1): 17-25. PMID11734332. doi:10.1016/S0304-3835(01)00718-2.
Gao H, Wu L, Kuroyanagi M, et al. (noviembre de 2003). «Antitumor-promoting constituents from Chaenomeles sinensis KOEHNE and their activities in JB6 mouse epidermal cells». Chemical & Pharmaceutical Bulletin51 (11): 1318-21. PMID14600382. doi:10.1248/cpb.51.1318.
Abe F, Yamauchi T, Nagao T, et al. (noviembre de 2002). «Ursolic acid as a trypanocidal constituent in rosemary». Biological & Pharmaceutical Bulletin25 (11): 1485-7. PMID12419966. doi:10.1248/bpb.25.1485.
Ji ZN, Ye WC, Liu GG, Hsiao WL (noviembre de 2002). «23-Hydroxybetulinic acid-mediated apoptosis is accompanied by decreases in bcl-2 expression and telomerase activity in HL-60 Cells». Life Sciences72 (1): 1-9. PMID12409140. doi:10.1016/S0024-3205(02)02176-8.
Pisha E, Chai H, Lee IS, et al. (octubre de 1995). «Discovery of betulinic acid as a selective inhibitor of human melanoma that functions by induction of apoptosis». Nature Medicine1 (10): 1046-51. PMID7489361. doi:10.1038/nm1095-1046.