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Publication of FR669819ApublicationCriticalpatent/FR669819A/en
G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
FR669819D1929-02-181929-02-18
Improvement in the electrical equipment of gramophones
ExpiredFR669819A
(en)