New groups of planetary nebulae with peculiar dust chemistry towards the Galactic bulge S. K. Górny, J. V. Perea-Calderón, D. A. García-Hernández, P. García-Lario and R. Szczerba A&A, 516 (2010) A39 Published online: 24 June 2010 DOI: 10.1051/0004-6361/200913010