Exceptional AGN long-timescale X-ray variability: The case of PHL 1092G. Miniutti, W.N. Brandt, D.P. Schneider, A.C. Fabian, L.C. Gallo and Th. BollerEPJ Web of Conferences, 39 (2012) 06002DOI: https://doi.org/10.1051/epjconf/20123906002