M87

[References]

HEGRA: F.A. Aharonian et al., AA 403, L1 (2003)

H.E.S.S.: F. Aharonian et al. Science 314, 1424-1427 (2007)
            M.Beilicke et al., 30th ICRC (2007) / arXiv:0710.4057 [astro-ph] p.118

VERITAS: V.A. Acciari et al., ApJ 679, 397-403 (2008)

MAGIC: J. Albert et al., ApJ 685, L23 (2008)