A new formulation of higher parallel transport in higher gauge theory
  In this technical paper, we present a new formulation of higher parallel transport in strict higher gauge theory required for the rigorous construction of Wilson lines and surfaces. Our approach is based on an original notion of Lie crossed module cocycle and cocycle 1- and 2-gauge transformation with a non standard double category theoretic interpretation. We show its equivalence to earlier formulations. 
Emanuele Soncini and Roberto Zucchini
hep-th math-ph math.DG math.MP