High altitude observatory astro-geophysical memorandum No. 149 drought, cycles and statistics, February 24 1961

High altitude observatory astro-geophysical memorandum No. 149 drought, cycles and statistics, February 24 1961, - 06 PDT 10 Sub- 3 Box 19 Folder 12, Box: 19, Folder: 12. Philip Duncan Thompson Papers, - 06-PDT. National Center for Atmospheric Research (NCAR) Archives. https://aspace.archives.ucar.edu/repositories/2/archival_objects/1867 Accessed April 21, 2026.