Collaboration, H., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A., Anton, G., …Zechlin, H. (2010). VHE gamma-ray emission of PKS 2155-304: spectral and temporal variability. Astronomy & Astrophysics, 520, https://doi.org/10.1051/0004-6361/201014484