Huchra, J. (1985). "2237 + 0305: A new and unusual gravitational lens". Astronomical Journal90: 691–696. doi:10.1086/113777. Bibcode: 1985AJ.....90..691H.
Huchra, J. (1985). "2237 + 0305: A new and unusual gravitational lens". Astronomical Journal90: 691–696. doi:10.1086/113777. Bibcode: 1985AJ.....90..691H.