http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Magnetic observation of sunspots, 1917-1924
2 volumes : illustrations, 8 plates on 4 ., diagrams ; 31 X 23 cm.
[by] George E. Hale [and] Seth B. Nicholson.
Papers of the Mount Wilson observatory, volume v, pt. 1-2.
Papers of the Mount Wilson Observatory ; v. 5, pt. 1-2