Line intensity: Out of the hundreds of papers with spectroscopic
observations of AGNs only a few will be mentioned here. They all
contain a large number of observations and provide good examples of
the available data.
Low redshift quasars: Baldwin (1975)
Intermediate redshift quasars: Wills, Netzer and Wills (1985).
High redshift quasars: Baldwin and Netzer (1978), Osmer and Smith (1980), Sargent, Steidel and Boksenberg (1989), Schneider, Schmidt and Gunn (1989, z > 4 quasars).
Seyfert 1 galaxies: Osterbrock (1977, 1984, optical spectrum), Morris and Ward (1988, near IR), Persson (1988, near IR), Osterbrock et al. (1990, near IR), Wu et al (1983, ultraviolet spectra), Cohen (1983, narrow lines in broad line objects).
Seyfert 2 galaxies: Koski (1978, optical lines) and Ferland and Osterbrock (1986, ultraviolet lines).
LINERs: Keel (1983), Filippenko and Sargent (1985) and Bonatto et al. (1989).
Molecules in AGNs: Kawara et al. (1990).
Line variability: A comprehensive review of all observations until 1988 is given by Peterson (1988). More recent emission line variability is described in Maoz et al (1991, detailed optical study of NGC 4151); Clavel et al (1990, best ultraviolet variability data of a type 1 Seyfert, NGC 5548); Peterson et al. (1991, best optical variability data of a type 1 Seyfert. NGC 5548); Zheng (1988, low redshift quasars), Perez et al. (1988, OVVs) and Gondhalekhar (1990, IUE observed quasars). For "vanishing" broad lines see Penston and Perez (1984). Narrow line variability is discussed in Clavel and Wamsteker (1987).
Line profiles: The following is a partial list of references, covering
many of the important aspects:
Line profiles in bright AGNs, including profile comparison: Baldwin and Netzer (1978). Wilkes and Carswell (1982), Wilkes (1986), Mathews and Wampler (1985).
Broad line profiles in faint AGNs: Osterbrock and Shuder (1982), De Robertis (1985), Crenshaw (1986), Stirpe et al. (1989). Wamsteker et al. (1990).
Profiles changes: Stirpe et al. (1989), Zheng and O'Brien (1990) and references therein.
Narrow line profiles: Whittle (1985a, 1985b). De Robertis and Osterbrock (1984, 1986), Busko and Steiner (1989).
Relative redshift of broad emission lines: Gaskell (1982), Wilkes (1986), Espey et al (1989), Sulentic (1989) and Corbin (1990).
Disk-type line profiles: Osterbrock, Koski and Phillips (1986), Perez et al. (1987), Halpern and Filippenko (1988, a spectacular example of a double hump