@incollection{Kahn,
    doi = {10.1007/bfb0039592},
    url = {https://doi.org/10.1007%2Fbfb0039592},
    publisher = {Springer-Verlag},
    pages = {22--39},
    author = {G. Kahn},
    title = {Natural semantics},
    booktitle = {{STACS} 87}
}

@incollection{Kahn, doi = {10.1007/bfb0039592}, url = {https://doi.org/10.1007%2Fbfb0039592}, publisher = {Springer-Verlag}, pages = {22--39}, author = {G. Kahn}, title = {Natural semantics}, booktitle = {{STACS} 87} }