IC 4663 - Hubble Space Telescope - Hajian, Balick, Terzian, Panagia, Bond (RGB: [OIII], [NII], linear V)
IC 4663 - Schwarz, H. E., Corradi, R.L.M., Melnick, J 1992 A&A Suppl, 96, 23 (RGB: Halha + [NII], [OIII])