Age dependent defect in vascular endothelial growth factor expression is associated with reduced hypoxia-inducible factor 1 activity. - Rivard,A.; Berthou-Soulie,L.; Principe,N.; Kearney,M.; Curry,C.; Branellec,D.; Semenza,G.L.; Isner,J.M. (J Biol Chem, 2000)