Titles written by J.F. Hellwig:
Number of documents found: 1
- J.F. Hellwig
Title: Time service of the U.S. Naval Observatory
Other Keywords: electric clocks time service vault Shortt clocks
Parent Document ID: 6223 - Parent Document Title: Transactions of the AIEE
chapter or other location info e.g. year vol no: 1932 jun
Page or pages: 538 - 540
BHM No: 8468
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