@inproceedings{Gottlob,
    doi = {10.1109/lics.2002.1029828},
    url = {https://doi.org/10.1109%2Flics.2002.1029828},
    publisher = {{IEEE} Comput. Soc},
    author = {G. Gottlob and C. Koch},
    title = {Monadic queries over tree-structured data},
    booktitle = {Proceedings 17th Annual {IEEE} Symposium on Logic in Computer Science}
}

@inproceedings{Gottlob, doi = {10.1109/lics.2002.1029828}, url = {https://doi.org/10.1109%2Flics.2002.1029828}, publisher = {{IEEE} Comput. Soc}, author = {G. Gottlob and C. Koch}, title = {Monadic queries over tree-structured data}, booktitle = {Proceedings 17th Annual {IEEE} Symposium on Logic in Computer Science} }