@article{de_Bruijn_1981,
    doi = {10.1016/1385-7258(81)90017-2},
    url = {https://doi.org/10.1016%2F1385-7258%2881%2990017-2},
    year = {1981},
    publisher = {Elsevier {BV}},
    volume = {84},
    number = {1},
    pages = {53--66},
    author = {N.G. de Bruijn},
    title = {Algebraic theory of Penrose{\textquotesingle}s non-periodic tilings of the plane. {II}},
    journal = {Indagationes Mathematicae (Proceedings)}
}

@article{de_Bruijn_1981, doi = {10.1016/1385-7258(81)90017-2}, url = {https://doi.org/10.1016%2F1385-7258%2881%2990017-2}, year = {1981}, publisher = {Elsevier {BV}}, volume = {84}, number = {1}, pages = {53--66}, author = {N.G. de Bruijn}, title = {Algebraic theory of Penrose{\textquotesingle}s non-periodic tilings of the plane. {II}}, journal = {Indagationes Mathematicae (Proceedings)} }