Lens candidates in the Capodimonte Deep Field in the vicinity of the   CSL1 object
  CSL1 is a peculiar object discovered in the OACDF. Photometric and spectroscopic investigation strongly suggest that it may be the first case of gravitational lensing by cosmic string. In this paper we derive and discuss a statistical excess of a gravitational lens candidates present in OACDF region surrounding CSL1. This excess cannot be explained on the basis of conventional gravitational lens statistic alone, but is compatible with the proposed cosmic string scenario. 
M.V.Sazhin, O.S.Khovanskaya, M.Capaccioli, G.Longo, J.M.Alcala,   R.Silvotti, M.V.Pavlov