Justification Logics with Common Knowledge

First of all, I would like to thank Prof. Dr. Gerhard Jäger, who has made this thesis possible and whose guidance and advice I value very much. Many thanks also to the members of the Logic and Theory group of the Institut für angewandte Mathematik und Informatik and the Logic Group of the Mathematisches Institut of the University of Bern, who have provided an inspiring environment. In particular, I would like t