@article{Broadbent_2021,
    doi = {10.1145/3452917},
    url = {https://doi.org/10.1145%2F3452917},
    year = {2021},
    month = {apr},
    publisher = {Association for Computing Machinery ({ACM})},
    volume = {22},
    number = {2},
    pages = {1--37},
    author = {Christopher H. Broadbent and Arnaud Carayol and C.-H. Luke Ong and Olivier Serre},
    title = {Higher-order Recursion Schemes and Collapsible Pushdown Automata: Logical Properties},
    journal = {{ACM} Transactions on Computational Logic}
}

@article{Broadbent_2021, doi = {10.1145/3452917}, url = {https://doi.org/10.1145%2F3452917}, year = {2021}, month = {apr}, publisher = {Association for Computing Machinery ({ACM})}, volume = {22}, number = {2}, pages = {1--37}, author = {Christopher H. Broadbent and Arnaud Carayol and C.-H. Luke Ong and Olivier Serre}, title = {Higher-order Recursion Schemes and Collapsible Pushdown Automata: Logical Properties}, journal = {{ACM} Transactions on Computational Logic} }