@inproceedings{Gyssens_1990,
    doi = {10.1145/298514.298593},
    url = {https://doi.org/10.1145%2F298514.298593},
    year = {1990},
    publisher = {{ACM} Press},
    author = {Marc Gyssens and Jan Paredaens and Dirk van Gucht},
    title = {A graph-oriented object database model},
    booktitle = {Proceedings of the ninth {ACM} {SIGACT}-{SIGMOD}-{SIGART} symposium on Principles of database systems  - {PODS} {\textquotesingle}90}
}

@inproceedings{Gyssens_1990, doi = {10.1145/298514.298593}, url = {https://doi.org/10.1145%2F298514.298593}, year = {1990}, publisher = {{ACM} Press}, author = {Marc Gyssens and Jan Paredaens and Dirk van Gucht}, title = {A graph-oriented object database model}, booktitle = {Proceedings of the ninth {ACM} {SIGACT}-{SIGMOD}-{SIGART} symposium on Principles of database systems - {PODS} {\textquotesingle}90} }