Strömgren uvby photometry of the open clusters NGC 6192 and NGC 6451 E. Paunzen, H. M. Maitzen, K. D. Rakos and J. Schombert A&A, 403 3 (2003) 937-941 Published online: 23 May 2003 DOI: 10.1051/0004-6361:20030443