@inproceedings{Gordon_1978,
    doi = {10.1145/512760.512773},
    url = {https://doi.org/10.1145%2F512760.512773},
    year = {1978},
    publisher = {{ACM} Press},
    author = {M. Gordon and R. Milner and L. Morris and M. Newey and C. Wadsworth},
    title = {A Metalanguage for interactive proof in {LCF}},
    booktitle = {Proceedings of the 5th {ACM} {SIGACT}-{SIGPLAN} symposium on Principles of programming languages  - {POPL} {\textquotesingle}78}
}

@inproceedings{Gordon_1978, doi = {10.1145/512760.512773}, url = {https://doi.org/10.1145%2F512760.512773}, year = {1978}, publisher = {{ACM} Press}, author = {M. Gordon and R. Milner and L. Morris and M. Newey and C. Wadsworth}, title = {A Metalanguage for interactive proof in {LCF}}, booktitle = {Proceedings of the 5th {ACM} {SIGACT}-{SIGPLAN} symposium on Principles of programming languages - {POPL} {\textquotesingle}78} }