XMM Cluster Survey: X-ray source identification using the Sloan Digital Sky Survey
Preprint published in 2004 by
Kate R. Land,
Robert C. Nichol,
Michael Davidson,
Kivanc Sabirli,
A. Kathy Romer,
Andrew R. Liddle,
Chris A. Collins,
Scott T. Kay 
,
Robert G. Mann,
Pedro T. P. Viana,
Michael J. West
,
Robert G. Mann,
Pedro T. P. Viana,
Michael J. West
