参考资料. Principal ∞-bundles — General theory [NikolausSchreiberStevensonPB]

@article{Nikolaus_2014,
   title={Principal $$\infty $$ ∞ -bundles: general theory},
   volume={10},
   ISSN={1512-2891},
   url={http://dx.doi.org/10.1007/s40062-014-0083-6},
   DOI={10.1007/s40062-014-0083-6},
   number={4},
   journal={Journal of Homotopy and Related Structures},
   publisher={Springer Science and Business Media LLC},
   author={Nikolaus, Thomas and Schreiber, Urs and Stevenson, Danny},
   year={2014},
   month=jun, pages={749–801} }