Baldis, H.Bolton, P.Chen, P.Cline, D.Ng, J. S. T.2004-12-032004-12-0320012001http://hdl.handle.net/2003/183910.17877/DE290R-11583enThe American Physical SocietyPhysical Review Letters530Observation of Plasma Focusing of a 28.5 GeV Positron Beam10.1103/PhysRevLett.87.244801article (journal)