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The United States and the metric system
Holt, Susan Fraker, (1972)
Map of standard time zones of the United States and adjacent parts of Canada and Mexico, as of June 1, 1962 : Interstate Commerce Commission
(1962)
SI-Einheiten : Gesetzliche Einheiten und ihre Anwendungspflicht in der Praxis ab 1978
Rümcker, Burkhard, (1978)