Flavonoid-rich dark chocolate improves endothelial function and increases plasma epicatechin concentrations in healthy adults - Engler, M B; Engler, M M; Chen, C Y; Malloy, M J; Browne, A; Chiu, E Y; Kwak, H K; Milbury, P; Paul, S M; Blumberg, J; Mietus-Snyder, M L (J Am Coll Nutr, 2004)