Aharonian, F., Akhperjanian, A., Bazer-Bachi, A., Behera, B., Beilicke, M., Benbow, W., …Zdziarski, A. (2007). An exceptional very high energy gamma-ray flare of PKS 2155-304. Astrophysical Journal, 664(2, 2), L71-L74. https://doi.org/10.1086/520635