Herschel, William (1785). "On the construction of the heavens". Philosophical Transactions of the Royal Society of London. 75: 213–266. From p. 262: "There is a very considerable, broad, pretty faint, small nebula near it [the Andromeda galaxy, M31]; my Sister [Caroline] discovered it August 27, 1783, with a Newtonian 2-feet sweeper. It shews the same faint colour with the great one, and is, no doubt, in the neighborhood of it. It is not [M32] … ; but this is about two-thirds of a degree north preceding it, in a line parallel to β [Beta] and ν [Nu] Andromedae."
Ford, Holland C.; et al. (July 1973), "Planetary Nebulae in Local-Group Galaxies. I. Identifications in NGC 185, NGC 205, and NGC 221", Astrophysical Journal, 183: L73, Bibcode:1973ApJ...183L..73F, doi:10.1086/181255
Ford, Holland C.; et al. (July 1973), "Planetary Nebulae in Local-Group Galaxies. I. Identifications in NGC 185, NGC 205, and NGC 221", Astrophysical Journal, 183: L73, Bibcode:1973ApJ...183L..73F, doi:10.1086/181255