A survey of the ISM in early-type galaxies. I. The ionized gas F. Macchetto, M. Pastoriza, N. Caon, W. B. Sparks, M. Giavalisco, R. Bender and M. Capaccioli Astron. Astrophys. Suppl. Ser., 120 3 (1996) 463-488 Published online: 15 December 1996 DOI: 10.1051/aas:1996307