ROMANIUK, Ryszard S. POLFEL - Free Electron Laser in Poland. Photonics Letters of Poland, [S. l.], v. 1, n. 3, p. pp. 103–105, 2009. DOI: 10.4302/photon. lett. pl.v1i3.54. Disponível em: https://photonics.pl/PLP/index.php/letters/article/view/1-35. Acesso em: 4 may. 2024.