@incollection{Robson_1999,
    doi = {10.1007/3-540-49116-3_20},
    url = {https://doi.org/10.1007%2F3-540-49116-3_20},
    year = {1999},
    publisher = {Springer Berlin Heidelberg},
    pages = {217--226},
    author = {John Michael Robson and Volker Diekert},
    title = {On Quadratic Word Equations},
    booktitle = {{STACS} 99}
}

@incollection{Robson_1999, doi = {10.1007/3-540-49116-3_20}, url = {https://doi.org/10.1007%2F3-540-49116-3_20}, year = {1999}, publisher = {Springer Berlin Heidelberg}, pages = {217--226}, author = {John Michael Robson and Volker Diekert}, title = {On Quadratic Word Equations}, booktitle = {{STACS} 99} }