Editing Fifth force (section)

===Cepheid variables===
Jain ''et al.'' (2012)<ref>{{cite journal |last1=Jain |first1=Bhuvnesh |last2=Vikram |first2=Vinu |last3=Sakstein |first3=Jeremy |date=25 November 2013 |title=Astrophysical tests of modified gravity: Constraints from distance indicators in the nearby universe |journal=The Astrophysical Journal |volume=779 |issue=1 |page=39 |id=39 |arxiv=1204.6044 |doi=10.1088/0004-637X/779/1/39 |bibcode=2013ApJ...779...39J|s2cid=119260435 }}</ref><!-- removed second ref to identical article (arXiv, bibcode, volume, journal page, etc.) listing these persons as authors: |last1=Cicoli |first1=Michele |last2=Pedro |first2=Francisco G. |last3=Tasinato |first3=Gianmassimo |year=1=2012 ; They are not listed in the indicated article -- lost ref from failure to fill in copied template? --> examined existing data on the rate of pulsation of over a thousand [[cepheid variable]] stars in 25&nbsp;galaxies. Theory suggests that the rate of cepheid pulsation in galaxies screened from a hypothetical fifth force by neighbouring clusters, would follow a different pattern from cepheids that are not screened. They were unable to find any variation from Einstein's theory of gravity.