@incollection{Blackburn_2007,
    doi = {10.1016/s1570-2464(07)80004-8},
    url = {https://doi.org/10.1016%2Fs1570-2464%2807%2980004-8},
    year = {2007},
    publisher = {Elsevier},
    pages = {1--84},
    author = {Patrick Blackburn and Johan van Benthem},
    title = {1 Modal logic: a semantic perspective},
    booktitle = {Handbook of Modal Logic}
}

@incollection{Blackburn_2007, doi = {10.1016/s1570-2464(07)80004-8}, url = {https://doi.org/10.1016%2Fs1570-2464%2807%2980004-8}, year = {2007}, publisher = {Elsevier}, pages = {1--84}, author = {Patrick Blackburn and Johan van Benthem}, title = {1 Modal logic: a semantic perspective}, booktitle = {Handbook of Modal Logic} }