Index Catalogue of Nebulæ found in the Years 1888 to 1894, With Notes and Corrections to the New General Catalogue by J. L. E. Dreyer, Ph.D.
and
Second Index Catalogue of Nebulæ and Cluster of Stars Containing Objects found in the Years 1895 to 1907 by by J. L. E. Dreyer, Ph.D.
