@article{Tarski_1941,
    doi = {10.2307/2268577},
    url = {https://doi.org/10.2307%2F2268577},
    year = {1941},
    month = {sep},
    publisher = {Cambridge University Press ({CUP})},
    volume = {6},
    number = {3},
    pages = {73--89},
    author = {Alfred Tarski},
    title = {On the calculus of relations},
    journal = {Journal of Symbolic Logic}
}

@article{Tarski_1941, doi = {10.2307/2268577}, url = {https://doi.org/10.2307%2F2268577}, year = {1941}, month = {sep}, publisher = {Cambridge University Press ({CUP})}, volume = {6}, number = {3}, pages = {73--89}, author = {Alfred Tarski}, title = {On the calculus of relations}, journal = {Journal of Symbolic Logic} }