@article{Alu2019, author = "Andrea Alu and Michele Cotrufo", title = "{3890138.pdf}", year = "2019", month = "6", url = "https://opticapublishing.figshare.com/articles/journal_contribution/3890138_pdf/8120762", doi = "10.6084/m9.figshare.8120762.v1" }