@article{Hoare_1971,
    doi = {10.1145/362452.362489},
    url = {https://doi.org/10.1145%2F362452.362489},
    year = {1971},
    month = {jan},
    publisher = {Association for Computing Machinery ({ACM})},
    volume = {14},
    number = {1},
    pages = {39--45},
    author = {C. A. R. Hoare},
    title = {Proof of a program},
    journal = {Communications of the {ACM}}
}

@article{Hoare_1971, doi = {10.1145/362452.362489}, url = {https://doi.org/10.1145%2F362452.362489}, year = {1971}, month = {jan}, publisher = {Association for Computing Machinery ({ACM})}, volume = {14}, number = {1}, pages = {39--45}, author = {C. A. R. Hoare}, title = {Proof of a program}, journal = {Communications of the {ACM}} }