@article{Negri_2005,
    doi = {10.1007/s10992-005-2267-3},
    url = {https://doi.org/10.1007%2Fs10992-005-2267-3},
    year = {2005},
    month = {oct},
    publisher = {Springer Science and Business Media {LLC}},
    volume = {34},
    number = {5-6},
    pages = {507--544},
    author = {Sara Negri},
    title = {Proof Analysis in Modal Logic},
    journal = {Journal of Philosophical Logic}
}

@article{Negri_2005, doi = {10.1007/s10992-005-2267-3}, url = {https://doi.org/10.1007%2Fs10992-005-2267-3}, year = {2005}, month = {oct}, publisher = {Springer Science and Business Media {LLC}}, volume = {34}, number = {5-6}, pages = {507--544}, author = {Sara Negri}, title = {Proof Analysis in Modal Logic}, journal = {Journal of Philosophical Logic} }