The 15–20 μm PAH emission features: probes of individual PAHs? C. Boersma, C. W. Bauschlicher Jr., L. J. Allamandola, A. Ricca, E. Peeters and A. G. G. M. Tielens A&A, 511 (2010) A32 Published online: 02 March 2010 DOI: 10.1051/0004-6361/200912714