U.S. Naval Observatory, Washington. Armature and field magnets of two-phase synchronous motor which drives micrometer (titre original)

inconnu, “U.S. Naval Observatory, Washington. Armature and field magnets of two-phase synchronous motor which drives micrometer (titre original),” Bibliothèque numérique - Observatoire de Paris, consulté le 19 novembre 2024, https://bibnum.obspm.fr/ark:/11287/1CRWL.