1. Aasen AJ, Borch G, Liaaen-Jensen S (1972) Carotenoids of flexibacteria V. chirality of zeaxanthin from different natural sources. Acta Chem Scand 26:404–405
2. Bartlett L, Klyne W, Mose WP, Scopes PM, Galasko G, Mallams AK, Weedon BCL, Szabolcs J, Toth G (1969) Optical rotatory dispersion of carotenoids. J Chem Soc Perkin 1:2527–2544
3. Britton G, Liaaen-Jensen S, Pfander H (1995) Carotenoids today and challenges for the future. In: Britton G, Liaaen-Jensen S, Pfander H (eds) Carotenoids 1A: isolation and analysis, 1st edn. Birkhäuser Verlag Basel, Berlin, pp 13–26
4. BVL (2007) Zusatzstoffe zugelassen nach Richtlinie 70/524/EWG und Übergangsregelung Verordnung EG 1831/2003. Bundesamt für Verbraucherschutz und Lebensmittelsicherheit.
5. Choi SK, Matsuda S, Hoshino T, Peng X, Misawa N (2006) Characterization of bacterial beta-carotene 3, 3′-hydroxylases, CrtZ, and P450 in astaxanthin biosynthetic pathway and adonirubin production by gene combination in Escherichia coli. Appl Microbiol Biotechnol 72:1238–1246