@article{Beck:201998, author = "Beck, Marvin and Arbet-Engels, Axel and Baack, Dominik and Balbo, Matteo and Biland, Adrian and Blank, Michael and Bretz, Thomas and Bruegge, Kai and Bulinski, Michael and Buss, Jens and Doerr, Manuel and Dorner, Daniela and Elsaesser, Dominik and Hildebrand, Dorothee and Iotov, Roman and Klinger, Marc and Mannheim, Karl and mueller, Sebastian and Neise, Dominik and Neronov, Andrii and Noethe, Maximilian and Paravac, Aleksander and Rhode, Wolfgang and Schleicher, Bernd and Sedlaczek, Kevin and Shukla, Amit and Sliusar, Vitalii and Tani, Laurits and Theissen, Fabian and Walter, Roland and von Willert, Elan", title = "{FACT - Probing the Periodicity of Mrk 421 and Mrk 501}", doi = "10.22323/1.358.0630", journal = "PoS", year = 2019, volume = "ICRC2019", pages = "630" }