@article{H_jek_1995,
    doi = {10.1016/0165-0114(94)00299-m},
    url = {https://doi.org/10.1016%2F0165-0114%2894%2900299-m},
    year = {1995},
    month = {aug},
    publisher = {Elsevier {BV}},
    volume = {73},
    number = {3},
    pages = {359--363},
    author = {Petr H{\'{a}}jek},
    title = {Fuzzy logic and arithmetical hierarchy},
    journal = {Fuzzy Sets and Systems}
}

@article{H_jek_1995, doi = {10.1016/0165-0114(94)00299-m}, url = {https://doi.org/10.1016%2F0165-0114%2894%2900299-m}, year = {1995}, month = {aug}, publisher = {Elsevier {BV}}, volume = {73}, number = {3}, pages = {359--363}, author = {Petr H{\'{a}}jek}, title = {Fuzzy logic and arithmetical hierarchy}, journal = {Fuzzy Sets and Systems} }