Multiwavelength study of the TeV blazar Mrk 421 during a giant flare A. Shukla, V. R. Chitnis, P. R. Vishwanath, B. S. Acharya, G. C. Anupama, P. Bhattacharjee, R. J. Britto, T. P. Prabhu, L. Saha and B. B. Singh A&A, 541 (2012) A140 Published online: 16 May 2012 DOI: 10.1051/0004-6361/201118569