+@Article{thomas27,
+ title = "The calculation of atomic fields",
+ author = "L. H. Thomas",
+ journal = "Mathematical Proceedings of the Cambridge
+ Philosophical Society",
+ volume = "23",
+ pages = "542--548",
+ year = "1927",
+ doi = "10.1017/S0305004100011683",
+}
+
+@Article{fermi27,
+ title = "",
+ author = "E. Fermi",
+ journal = "Atti Accad. Naz. Lincei, Cl. Sci. Fis. Mat. Nat.
+ Rend.",
+ volume = "6",
+ pages = "602",
+ year = "1927",
+}
+
+@Article{hartree28,
+ title = "The Wave Mechanics of an Atom with a Non-Coulomb
+ Central Field. Part {I}. Theory and Methods",
+ author = "D. R. Hartree",
+ journal = "Mathematical Proceedings of the Cambridge
+ Philosophical Society",
+ volume = "24",
+ pages = "89--110",
+ year = "1928",
+ doi = "10.1017/S0305004100011919",
+}
+
+@Article{slater29,
+ title = "The Theory of Complex Spectra",
+ author = "J. C. Slater",
+ journal = "Phys. Rev.",
+ volume = "34",
+ number = "10",
+ pages = "1293--1322",
+ numpages = "29",
+ year = "1929",
+ month = nov,
+ doi = "10.1103/PhysRev.34.1293",
+ publisher = "American Physical Society",
+}
+