@article{ref1,
  author = "S. M. O'Brien and D. R. Clarke and J. P. Jacobs and M. L. Jacobs and F. G. Lacour-Gayet and C. Pizarro and K. F. Welke and B. Maruszewski and Z. Tobota and W. J. Miller and L. Hamilton and E. D. Peterson and C. Mavroudis and F. H. Edwards",
  title = "An empirically based tool for analyzing mortality associated with congenital heart surgery",
  year = 2009,
  journal = "The Journal of Thoracic and Cardiovascular Surgery",
  publisher = "Elsevier",
  volume = 138,
  number = 5,
  pages = "1139-1153",
  month = "Nov",
  doi = "10.1016/j.jtcvs.2009.03.071",
  url = "http://dx.doi.org/10.1016/j.jtcvs.2009.03.071"
}