Ångström, A.J. (1852). "Optiska undersökningar" [Optical investigations]. Kongliga Vetenskaps-Akademiens Handlingar [Proceedings of the Royal Academy of Science] (بالسويدية). 40: 333–360. Archived from the original on 2020-05-22.
Ångström, A.J. (1852). "Optiska undersökningar" [Optical investigations]. Kongliga Vetenskaps-Akademiens Handlingar [Proceedings of the Royal Academy of Science] (بالسويدية). 40: 333–360. Archived from the original on 2020-05-22.