@incollection{F_rer_1980,
    doi = {10.1007/3-540-10003-2_74},
    url = {https://doi.org/10.1007%2F3-540-10003-2_74},
    year = {1980},
    publisher = {Springer Berlin Heidelberg},
    pages = {234--245},
    author = {Martin Fürer},
    title = {The complexity of the inequivalence problem for regular expressions with intersection},
    booktitle = {Automata, Languages and Programming}
}

@incollection{F_rer_1980, doi = {10.1007/3-540-10003-2_74}, url = {https://doi.org/10.1007%2F3-540-10003-2_74}, year = {1980}, publisher = {Springer Berlin Heidelberg}, pages = {234--245}, author = {Martin Fürer}, title = {The complexity of the inequivalence problem for regular expressions with intersection}, booktitle = {Automata, Languages and Programming} }