@article{Gronwall_1919,
    doi = {10.2307/1967124},
    url = {https://doi.org/10.2307%2F1967124},
    year = {1919},
    month = {jul},
    publisher = {{JSTOR}},
    volume = {20},
    number = {4},
    pages = {292},
    author = {T. H. Gronwall},
    title = {Note on the Derivatives with Respect to a Parameter of the Solutions of a System of Differential Equations},
    journal = {The Annals of Mathematics}
}

@article{Gronwall_1919, doi = {10.2307/1967124}, url = {https://doi.org/10.2307%2F1967124}, year = {1919}, month = {jul}, publisher = {{JSTOR}}, volume = {20}, number = {4}, pages = {292}, author = {T. H. Gronwall}, title = {Note on the Derivatives with Respect to a Parameter of the Solutions of a System of Differential Equations}, journal = {The Annals of Mathematics} }