An ordinal analysis of parameter free Π12-comprehension Michael Rathjen OriginalPaper 01 September 2004 Pages: 263 - 362
Models of set theory with definable ordinals Ali Enayat OriginalPaper 01 September 2004 Pages: 363 - 385
Diamond, square, and level by level equivalence Arthur W. Apter OriginalPaper 09 October 2004 Pages: 387 - 395