@article{Ratschan_2007,
    doi = {10.1145/1210268.1210276},
    url = {https://doi.org/10.1145%2F1210268.1210276},
    year = {2007},
    month = {feb},
    publisher = {Association for Computing Machinery ({ACM})},
    volume = {6},
    number = {1},
    pages = {8},
    author = {Stefan Ratschan and Zhikun She},
    title = {Safety verification of hybrid systems by constraint propagation-based abstraction refinement},
    journal = {{ACM} Transactions on Embedded Computing Systems}
}

@article{Ratschan_2007, doi = {10.1145/1210268.1210276}, url = {https://doi.org/10.1145%2F1210268.1210276}, year = {2007}, month = {feb}, publisher = {Association for Computing Machinery ({ACM})}, volume = {6}, number = {1}, pages = {8}, author = {Stefan Ratschan and Zhikun She}, title = {Safety verification of hybrid systems by constraint propagation-based abstraction refinement}, journal = {{ACM} Transactions on Embedded Computing Systems} }