The Time Delay in the Gravitational Lens PKS 1830-211
  We have measured a time delay of 26 (+4/-5) days and a magnification ratio of 1.52 +/- 0.05 in the strong radio gravitational lens PKS 1830-211. The observations were made over the 18 month period from 1997 January to 1998 July with the Australia Telescope Compact Array at 8.6 GHz, and have shown that the source started a large flux density outburst around 1997 June. 
J. E. J. Lovell, D. L. Jauncey, J. E. Reynolds, M. H. Wieringa, E. A.   King, A. K. Tzioumis, P. M. McCulloch and P. G. Edwards