@article{Shapiro_1959,
    doi = {10.1002/cpa.3160120306},
    url = {https://doi.org/10.1002%2Fcpa.3160120306},
    year = {1959},
    month = {aug},
    publisher = {Wiley},
    volume = {12},
    number = {3},
    pages = {487--500},
    author = {Harold N. Shapiro},
    title = {On a theorem concerning exponential polynomials},
    journal = {Communications on Pure and Applied Mathematics}
}

@article{Shapiro_1959, doi = {10.1002/cpa.3160120306}, url = {https://doi.org/10.1002%2Fcpa.3160120306}, year = {1959}, month = {aug}, publisher = {Wiley}, volume = {12}, number = {3}, pages = {487--500}, author = {Harold N. Shapiro}, title = {On a theorem concerning exponential polynomials}, journal = {Communications on Pure and Applied Mathematics} }