NAKAMURA, Takashi; SATO, Katsuyuki; AKIBA, Mitsuo; OHNISHI, Masao (2006). “Urobilinogen, as a Bile Pigment Metabolite, Has an Antioxidant Function”. Journal of Oleo Science55 (4): 191–197. doi:10.5650/jos.55.191. ISSN1345-8957.
NAKAMURA, Takashi; SATO, Katsuyuki; AKIBA, Mitsuo; OHNISHI, Masao (2006). “Urobilinogen, as a Bile Pigment Metabolite, Has an Antioxidant Function”. Journal of Oleo Science55 (4): 191–197. doi:10.5650/jos.55.191. ISSN1345-8957.