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. Prada A&A, 370 2 (2001) 456-467 Published online: 15 May 2001 DOI: 10.1051/0004-6361:20010220