New abundances of southern planetary nebulae R. D.D. Costa, C. Chiappini, W. J. Maciel and J.A. de Freitas Pacheco Astron. Astrophys. Suppl. Ser., 116 2 (1996) 249-256 Published online: 15 April 1996 DOI: 10.1051/aas:1996112