Observations of narrow line AGNs: See chapter 2. The narrow line spectrum of Seyfert 1 galaxies is discussed by Cohen (1983).
NLXGs and dust: The relation between optical and X-ray properties, and the correlation with inclination and reddening, is discussed by Lawrence and Elvis (1982). More references can be found in a review article by Lawrence (1987).
Seyfert 2 galaxies: Polarization measurements: The first paper is by Antonucci and Miller (1985). More recent work is by Miller and Goodrich (1990). For models see Krolik and Begelman (1988).
LINERs: Useful review articles are Keel (1985) and Filippenko (1989). For basic observations see chapter 2. Evidence for broad H and a large range of densities is given by Filippenko and Sargent (1985, 1988).
Diagnostic diagrams: See Baldwin et al. (1981), Veilleux and Osterbrock (1987) and Kirhakos and Phillips (1989). For a discussion on the use of [SII] and [SIII] lines see Diaz et al. (1985) and Kirhakos and Phillips (1989).
Shock wave models: See Shull and McKee (1979) and Binette et al. (1984).
Photoionization models: See Ferland and Netzer (1983), Halpern and Steiner (1983), Stasinska (1984, multi-component model) and Binnette (1985, abundances) for photoionization by a power-law continuum. See Pequignot (1984) for ionization by a blackbody source.
Composite models: The basic idea and most theoretical calculations are by Contini and Aldrovandi. See Viegas-Aldrovandi and Contini (1989) for references.