Textos:
S. Sontz. Principal Bundles: The Classical Case, Springer-Verlag, 2015.
D. Husemöller et al. Basic Bundle Theory and K-Cohomology Invariants, Lect. Notes Phys. 726, Springer-Verlag, 2008.
C.H. Taubes. Differential Geometry: Bundles, Connections, Metrics and Curvature, Oxford University Press, 2011.