SBS 1150+599A: An extremely oxygen-poor planetary nebula in the Galactic halo?G. H. Tovmassian, G. Stasińska, V. H. Chavushyan, S. V. Zharikov, C. Gutierrez and F. PradaA&A, 370 2 (2001) 456-467DOI: https://doi.org/10.1051/0004-6361:20010220