@inproceedings{Lewis_1965,
    doi = {10.1109/focs.1965.14},
    url = {https://doi.org/10.1109%2Ffocs.1965.14},
    year = {1965},
    publisher = {{IEEE}},
    author = {P. M. Lewis and R. E. Stearns and J. Hartmanis},
    title = {Memory bounds for recognition of context-free and context-sensitive languages},
    booktitle = {6th Annual Symposium on Switching Circuit Theory and Logical Design ({SWCT} 1965)}
}

@inproceedings{Lewis_1965, doi = {10.1109/focs.1965.14}, url = {https://doi.org/10.1109%2Ffocs.1965.14}, year = {1965}, publisher = {{IEEE}}, author = {P. M. Lewis and R. E. Stearns and J. Hartmanis}, title = {Memory bounds for recognition of context-free and context-sensitive languages}, booktitle = {6th Annual Symposium on Switching Circuit Theory and Logical Design ({SWCT} 1965)} }