@incollection{L_ding,
    doi = {10.1007/978-3-540-74456-6_8},
    url = {https://doi.org/10.1007%2F978-3-540-74456-6_8},
    publisher = {Springer Berlin Heidelberg},
    pages = {67--77},
    author = {Christof Löding and Alex Spelten},
    title = {Transition Graphs of Rewriting Systems over Unranked Trees},
    booktitle = {Mathematical Foundations of Computer Science 2007}
}

@incollection{L_ding, doi = {10.1007/978-3-540-74456-6_8}, url = {https://doi.org/10.1007%2F978-3-540-74456-6_8}, publisher = {Springer Berlin Heidelberg}, pages = {67--77}, author = {Christof Löding and Alex Spelten}, title = {Transition Graphs of Rewriting Systems over Unranked Trees}, booktitle = {Mathematical Foundations of Computer Science 2007} }