The effect of a low-fat spread with added plant sterols on vascular function markers: Results of the investigating vascular function effects of plant sterols (invest) study. Issue 1 (July 2015) - Ras, R.T.; Fuchs, D.; Koppenol, W.P.; Garczarek, U.; Greyling, A.; Keicher, C.; Verhoeven, C.; Bouzamondo, H.; Wagner, F.; Trautwein, E.A.