Kerodon

@article{MR0220279,
    AUTHOR = "Brown, R.",
    TITLE = "Groupoids and van {K}ampen's theorem",
    JOURNAL = "Proc. London Math. Soc. (3)",
    FJOURNAL = "Proceedings of the London Mathematical Society. Third Series",
    VOLUME = "17",
    YEAR = "1967",
    PAGES = "385--401",
    ISSN = "0024-6115",
    MRCLASS = "55.40",
    MRNUMBER = "0220279",
    MRREVIEWER = "R. H. Fox",
    DOI = "10.1112/plms/s3-17.3.385"
}