Candidate polar-ring galaxies in the Hubble Deep Field
  We discuss the properties of two peculiar galaxies (2-809 and 2-906) selected in the Hubble Deep Field as possible candidates to high-redshift (Z about 1) polar-ring galaxies. We found that the presence of polar-ring galaxies in a random deep field gives some support for a galaxy interaction rate steeply increasing with redshift. 
V.P.Reshetnikov (Astronomical Institute of St.Petersburg State   University, Russia)