1. Abbot, C. G., Fowle, F. E., Aldrich, L. B., and Hoover, W. H. (1908–1954). Annals of the Astrophysical Observatory of the Smithsonian Institution II–VII (see especially III, 99 and 113, and VII, 176), Washington, D.C.
2. On the atmospheric transmission of sun radiation and on dust in the air;Ångström;Geografis. Ann.,1929
3. On the atmospheric transmission of sun radiation II;Geografis. Ann.,1930
4. Techniques of determining the turbidity of the atmosphere;Ångström;Tellus,1961
5. Atmospheric turbidity, global illumination and planetary albedo of the earth;Ångström;Tellus,1962