120,000 quasars, only four of them seemed to act as a gravitational lens.

quasar SDSS J0013+1523
Astrophysicists discover a quasar that acts as a cosmic lens (w/ Video)
contains nearly a million galaxies and over 120,000 quasars.
A sample of some 23,000 of these quasars in the northern hemisphere was selected by the Laboratory of Astrophysics team.
In the end, only four of them seemed to act as a gravitational lens.
http://www.physorg.com/news198859065.html
Reverse cosmic lens advances quasar studies | W. M. Keck Observatory
the quasar is 1.6 billion light years from Earth and lenses a galaxy roughly 7.5 billion light years away.
http://keckobservatory.org/index.php/news/reverse_cosmic_lens_advances_quasar_studies/
Discovery of a Triple Quasar
http://www.astro.caltech.edu/~george/qsolens/

Quasars:

Quasar SDSS J0123+00
[1006.1517] VLT and GTC observations of SDSS J0123+00: a type 2 quasar triggered in a galaxy encounter?
http://es.arxiv.org/abs/1006.1517
Galaxy encounter fires up quasar : Royal Astronomical Society
In the case of SDSS J0123+00, one of the most important results is the discovery of an extended, faint nebula of ionized gas around the entire galaxy. The nebula is about six times larger than our own Milky Way Galaxy and, according to the authors, is probably made of the debris of the interaction between SDSS J0123+00 and its neighbour.
http://www.ras.org.uk//index.php?option=com_content&task=view&id=1776&Itemid=2
Galaxy encounter fires up quasar
http://www.physorg.com/news196621118.html
Galaxy encounter fires up quasar
http://www.sciencedaily.com/releases/2010/06/100624122444.htm
Galaxy Collision Fires Up Quasar - Space News - redOrbit
http://www.redorbit.com/news/space/1884298/galaxy_collision_fires_up_quasar/index.html

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Quasar 3C196
Details in the Structure of a distant Quasar
First high-resolution image from the LOFAR radio telescope array
MPIfR PR 06/2010 (1)
http://www.mpifr-bonn.mpg.de/public/pr/pr-3c196-en.html
MPA :: Details in the Structure of a distant Quasar
http://www.mpa-garching.mpg.de/mpa/institute/news_archives/news1006_lofar/news1006_lofar-en.html
Details in structure of a distant quasar: First high-resolution image from LOFAR radio telescope array
http://www.sciencedaily.com/releases/2010/06/100601083405.htm
Scientist Explains New LOFAR Image of Quasar 3C196 | Universe Today
http://www.universetoday.com/2010/06/02/scientist-explains-new-lofar-image-of-quasar-3c196/

Quasar - Wikipedia
http://en.wikipedia.org/wiki/Quasar





Major Galaxy Mergers and the Growth of Supermassive Black Holes in Quasars
銀河同士の合体とクェーサー中心での超大質量ブラックホールの成長 ［Science Express 掲載］
クェーサー：遠方に存在する、通常の銀河に比べ百倍以上の明るい光度をもつ活動銀河
http://www.sciencemag.org/cgi/content/abstract/328/5978/600