Simmons, Harold Hoyt, 1888–
Nationality: Undetermined, possibly 
(United States)
Identities and Authority Control
- pdbooks.info ID: 141333
Harold Hoyt Simmons Contributed to the Following:
| Title | Edition | Year of Publication | Role | Country of Publication | Possible Copyright Status | Available Online? | |||
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| The railway signal directory: an illustrated vocabulary of terms which designate American railway signals, their parts, attachments and details of construction, with descriptions of methods of operation and some illustrations of British signals and practice | 1911 | Author | |  | |  | |    
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