@article{lambek58,
 title = {The Mathematics of Sentence Structure},
 author = {Joachim Lambek},
 year = {1958},
 doi = {10.1080/00029890.1958.11989160},
 url = {https://doi.org/10.1080/00029890.1958.11989160},
 journal = {The American Mathematical Monthly},
 volume = {65},
 number = {3},
 pages = {154--170},
 publisher = {Taylor \& Francis}
}