@inproceedings{Pentus,
    doi = {10.1109/lics.1993.287565},
    url = {https://doi.org/10.1109%2Flics.1993.287565},
    publisher = {{IEEE} Comput. Soc. Press},
    author = {M. Pentus},
    title = {Lambek grammars are context free},
    booktitle = {[1993] Proceedings Eighth Annual {IEEE} Symposium on Logic in Computer Science}
}

@inproceedings{Pentus, doi = {10.1109/lics.1993.287565}, url = {https://doi.org/10.1109%2Flics.1993.287565}, publisher = {{IEEE} Comput. Soc. Press}, author = {M. Pentus}, title = {Lambek grammars are context free}, booktitle = {[1993] Proceedings Eighth Annual {IEEE} Symposium on Logic in Computer Science} }