Probing AGB nucleosynthesis via accurate Planetary Nebula abundances P. Marigo, J. Bernard-Salas, S. R. Pottasch, A. G. G. M. Tielens and P. R. Wesselius A&A, 409 2 (2003) 619-640 Published online: 17 November 2003 DOI: 10.1051/0004-6361:20030953