@article{article01134a5b,
title   = {Probing photoionization models in two well-studied extended emission-line regions: centaurus a and 3c227},
author = {Viegas, Sueli Maria Marino and Prieto, M A},
year = {1992},
doi = {10.1093/mnras/258.3.483},
journal   = {Monthly Notices of the Royal Astronomical Society}
}