@article{Wang_1995,
    doi = {10.1137/s0363012993246828},
    url = {https://doi.org/10.1137%2Fs0363012993246828},
    year = {1995},
    month = {jul},
    publisher = {Society for Industrial {\&} Applied Mathematics ({SIAM})},
    volume = {33},
    number = {4},
    pages = {1102--1126},
    author = {Yuan Wang and Eduardo D. Sontag},
    title = {Orders of Input/Output Differential Equations and State-Space Dimensions},
    journal = {{SIAM} Journal on Control and Optimization}
}

@article{Wang_1995, doi = {10.1137/s0363012993246828}, url = {https://doi.org/10.1137%2Fs0363012993246828}, year = {1995}, month = {jul}, publisher = {Society for Industrial {\&} Applied Mathematics ({SIAM})}, volume = {33}, number = {4}, pages = {1102--1126}, author = {Yuan Wang and Eduardo D. Sontag}, title = {Orders of Input/Output Differential Equations and State-Space Dimensions}, journal = {{SIAM} Journal on Control and Optimization} }