MOROSHKIN, P.; HOFER, A.; ULZEGA, S.; WEIS, A. Spectroscopy of atomic and molecular defects in solid 4He using optical, microwave, radio frequency, magnetic and electric fields (Review Article). ФІЗИКА НИЗЬКИХ ТЕМПЕРАТУР, Харків, Україна, v. 32, n. 11, p. 1297–1319, 2006. DOI: 10.1063/1.2389001. Disponível em: https://fnt.ilt.kharkov.ua/index.php/fnt/article/view/f32-1297e. Acesso em: 17 квіт. 2024.