@article{Hudak_1991,
    doi = {10.1145/103135.103139},
    url = {https://doi.org/10.1145%2F103135.103139},
    year = {1991},
    month = {apr},
    publisher = {Association for Computing Machinery ({ACM})},
    volume = {13},
    number = {2},
    pages = {269--290},
    author = {Paul Hudak and Jonathan Young},
    title = {Collecting interpretations of expressions},
    journal = {{ACM} Transactions on Programming Languages and Systems}
}

@article{Hudak_1991, doi = {10.1145/103135.103139}, url = {https://doi.org/10.1145%2F103135.103139}, year = {1991}, month = {apr}, publisher = {Association for Computing Machinery ({ACM})}, volume = {13}, number = {2}, pages = {269--290}, author = {Paul Hudak and Jonathan Young}, title = {Collecting interpretations of expressions}, journal = {{ACM} Transactions on Programming Languages and Systems} }