@incollection{Niwi_ski_1986,
    doi = {10.1007/3-540-16761-7_96},
    url = {https://doi.org/10.1007%2F3-540-16761-7_96},
    year = {1986},
    publisher = {Springer Berlin Heidelberg},
    pages = {464--473},
    author = {Damian Niwi{\'{n}}ski},
    title = {On fixed-point clones},
    booktitle = {Automata, Languages and Programming}
}

@incollection{Niwi_ski_1986, doi = {10.1007/3-540-16761-7_96}, url = {https://doi.org/10.1007%2F3-540-16761-7_96}, year = {1986}, publisher = {Springer Berlin Heidelberg}, pages = {464--473}, author = {Damian Niwi{\'{n}}ski}, title = {On fixed-point clones}, booktitle = {Automata, Languages and Programming} }