SOMMERBURG O ET AL: 'Simultaneous detection of carotenoids and vitamin E in human plasma', JOURNAL OF CHROMATOGRAPHY B: BIOMEDICAL SCIENCES & APPLICATIONS, ELSEVIER SCIENCE PUBLISHERS, NL, vol. 695, no. 2, 1 August 1997 (1997-08-01), pages 209 - 215, XP004125785, ISSN: 1570-0232