src/HOL/Computational_Algebra/document/root.bib

clarified signature;

@article{nowak2000,
  title={Some elementary proofs of {P}uiseux’s theorems},
  author={Nowak, Krzysztof Jan},
  journal={Univ. Iagel. Acta Math},
  volume={38},
  pages={279--282},
  year={2000}
}