Massive star formation in the central regions of spiral galaxies J. H. Knapen, L. M. Mazzuca, T. Böker, I. Shlosman, L. Colina, F. Combes and D. J. Axon A&A, 448 2 (2006) 489-498 Published online: 24 February 2006 DOI: 10.1051/0004-6361:20053928