Sphingosine-1-Phosphate Stimulates the Functional Capacity of Progenitor Cells by Activation of the CXCR <sub>4</sub> -Dependent Signaling Pathway via the S1P <sub>3</sub> ReceptorDirk Walter, Judith Haendeler, Johannes Reinhold et al.|Arteriosclerosis Thrombosis and Vascular Biology|2006Cited by 161