How Sommerfeld extended Bohr’s model of the atom (1913–1916) Michael Eckert OriginalPaper 30 January 2014 Pages: 141 - 156
On the theory of the Balmer series A. Sommerfeld Historical Document 30 January 2014 Pages: 157 - 177
The fine structure of Hydrogen and Hydrogen-like lines A. Sommerfeld Historical Document 30 January 2014 Pages: 179 - 204
Discovery of the hot Big Bang: What happened in 1948 Phillip James Edwin Peebles OriginalPaper 10 April 2014 Pages: 205 - 223
An international campaign of the 19th century to determine the solar parallax Andreas Schrimpf OriginalPaper 04 February 2014 Pages: 225 - 244
