The extended narrow line region of NGC 4151.: I. Emission line ratios and their implicationsM. V. Penston, R. Terlevich, I. Aretxaga et al.|LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas)|1990Cited by 7
Spectrscopic monitoring of active galactic nuclei. 3 : Size of the broad line region in NGC 3227I. Salamanca, I. Wanders, D. Alloin et al.|Leiden Repository (Leiden University)|1994Cited by 4