@article{Stengle_1974,
    doi = {10.1007/bf01362149},
    url = {https://doi.org/10.1007%2Fbf01362149},
    year = {1974},
    month = {jun},
    publisher = {Springer Science and Business Media {LLC}},
    volume = {207},
    number = {2},
    pages = {87--97},
    author = {Gilbert Stengle},
    title = {A nullstellensatz and a positivstellensatz in semialgebraic geometry},
    journal = {Mathematische Annalen}
}

@article{Stengle_1974, doi = {10.1007/bf01362149}, url = {https://doi.org/10.1007%2Fbf01362149}, year = {1974}, month = {jun}, publisher = {Springer Science and Business Media {LLC}}, volume = {207}, number = {2}, pages = {87--97}, author = {Gilbert Stengle}, title = {A nullstellensatz and a positivstellensatz in semialgebraic geometry}, journal = {Mathematische Annalen} }