  Justification logics are modal-like logics that provide a framework for
reasoning about justifications. This paper introduces labeled sequent calculi
for justification logics, as well as for hybrid modal-justification logics.
Using the method due to Sara Negri, we internalize the Kripke-style semantics
of justification logics, known as Fitting models, within the syntax of the
sequent calculus to produce labeled sequent calculus. We show that our labeled
sequent calculi enjoy a weak subformula property, all of the rules are
invertible and the structural rules (weakening and contraction) and cut are
admissible. Finally soundness and completeness are established, and termination
of proof search for some of the labeled systems are shown. We describe a
procedure, for some of the labeled systems, which produces a derivation for
valid sequents and a countermodel for non-valid sequents. We also show a model
correspondence for justification logics in the context of labeled sequent
calculus.
