@article{doi:10.1112/plms/s2-45.1.161,
    Author = {Turing, A. M.},
    EPrint = {https://londmathsoc.onlinelibrary.wiley.com/doi/pdf/10.1112/plms/s2-45.1.161},
    File = {SYSTEMS OF LOGIC BASED ON ORDINALS - turing1939 - a - a - a.pdf},
    Journal = {Proceedings of the London Mathematical Society},
    Number = {1},
    Pages = {161-228},
    Title = {Systems of Logic Based on Ordinals},
    URL = {https://londmathsoc.onlinelibrary.wiley.com/doi/abs/10.1112/plms/s2-45.1.161},
    Volume = {s2-45},
    Year = {1939},
    bdsk-url-1 = {https://londmathsoc.onlinelibrary.wiley.com/doi/abs/10.1112/plms/s2-45.1.161},
    bdsk-url-2 = {https://doi.org/10.1112/plms/s2-45.1.161},
    date-added = {2020-02-23 14:48:26 +0100},
    date-modified = {2020-02-23 14:48:36 +0100},
    doi = {10.1112/plms/s2-45.1.161}
}

@article{doi:10.1112/plms/s2-45.1.161, Author = {Turing, A. M.}, EPrint = {https://londmathsoc.onlinelibrary.wiley.com/doi/pdf/10.1112/plms/s2-45.1.161}, File = {SYSTEMS OF LOGIC BASED ON ORDINALS - turing1939 - a - a - a.pdf}, Journal = {Proceedings of the London Mathematical Society}, Number = {1}, Pages = {161-228}, Title = {Systems of Logic Based on Ordinals}, URL = {https://londmathsoc.onlinelibrary.wiley.com/doi/abs/10.1112/plms/s2-45.1.161}, Volume = {s2-45}, Year = {1939}, bdsk-url-1 = {https://londmathsoc.onlinelibrary.wiley.com/doi/abs/10.1112/plms/s2-45.1.161}, bdsk-url-2 = {https://doi.org/10.1112/plms/s2-45.1.161}, date-added = {2020-02-23 14:48:26 +0100}, date-modified = {2020-02-23 14:48:36 +0100}, doi = {10.1112/plms/s2-45.1.161} }