Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Nakai Shun-ichi and Ishii Takehiko and Sagawa Takasi,Core Exciton Absorption in Sodium Halides,Journal of the Physical Society of Japan,00319015,THE PHYSICAL SOCIETY OF JAPAN,1971,30,2,428-439,https://cir.nii.ac.jp/crid/1390001204196028288,https://doi.org/10.1143/jpsj.30.428