Hewlett-Packard 23S II RPN Scientific Calculator owner's manual, 1991

Hewlett-Packard 23S II RPN Scientific Calculator owner's manual, 1991, WBC Box 4 Item 57, Box: 4. William Bradley Calculator Collection, WBC. National Center for Atmospheric Research (NCAR) Archives. https://aspace.archives.ucar.edu/repositories/2/archival_objects/9451 Accessed June 15, 2026.