A VLBI Study of the Gravitational Lens JVAS B0218+357
  We present the results of phase-referenced VLBA+Effelsberg observations at five frequencies of the gravitational lens B0218+357 to establish the precise registration of the A and B lensed image positions. 
R. Mittal (1), R. Porcas (1), O. Wucknitz (2), A. Biggs (3) ((1)   MPIfR, Germany, (2) University of Potsdam, Germany, (3) J...