Regesta pontificum romanorum ab condita ecclesia ad annum post Christum natum MCXCVIII. - Jaffé, Philipp, 1819-1870, [from old catalog]; Wattenbach, Wilhelm, 1819-1897. [from old catalog]; Loewenfeld, Samuel, 1854- [from old catalog]; Kaltenbrunner, Ferdinand, [from old catalog]; Ewald, Paul, 1857-1911, [from old catalog] (Veit et comp., 1885)