@inproceedings{inproceedings0aa2d33b,
title   = {Helium and oxygen abundances in planetary nebulae of the small magellanic cloud},
author = {Costa, Roberto Dell'Aglio Dias da and Freitas Pacheco, José Antonio},
year = {1999},
publisher = {IAG-USP},
booktitle   = {International Astronomical Union}
}