+
+@Article{li93,
+ title = "Density-matrix electronic-structure method with linear
+ system-size scaling",
+ author = "X.-P. Li and R. W. Nunes and David Vanderbilt",
+ journal = "Phys. Rev. B",
+ volume = "47",
+ issue = "16",
+ pages = "10891--10894",
+ year = "1993",
+ month = apr,
+ doi = "10.1103/PhysRevB.47.10891",
+ URL = "http://link.aps.org/doi/10.1103/PhysRevB.47.10891",
+ publisher = "American Physical Society",
+}
+
+@Article{mauri93,
+ title = "Self-consistent first-principles technique with linear
+ scaling",
+ author = "E. Hern\'andez and M. J. Gillan",
+ journal = "Phys. Rev. B",
+ volume = "51",
+ issue = "15",
+ pages = "10157--10160",
+ year = "1995",
+ month = apr,
+ doi = "10.1103/PhysRevB.51.10157",
+ URL = "http://link.aps.org/doi/10.1103/PhysRevB.51.10157",
+ publisher = "American Physical Society",
+}
+
+@Article{hernandez95,
+ title = "Self-consistent first-principles technique with linear
+ scaling",
+ author = "E. Hern\'andez and M. J. Gillan",
+ journal = "Phys. Rev. B",
+ volume = "51",
+ issue = "15",
+ pages = "10157--10160",
+ year = "1995",
+ month = apr,
+ doi = "10.1103/PhysRevB.51.10157",
+ URL = "http://link.aps.org/doi/10.1103/PhysRevB.51.10157",
+ publisher = "American Physical Society",
+}