Collaboration, H., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A., Anton, G., …Collaboration, H. (2011). Search for Lorentz Invariance breaking with a likelihood fit of the PKS 2155-304 flare data taken on MJD 53944. Astroparticle Physics, 34(9), 738-747. https://doi.org/10.1016/j.astropartphys.2011.01.007