Astin & Karo 1959. Astin, A. V. & Karo, H. Arnold, (1959), Refinement of values for the yard and the pound, Washington, D.C.: National Bureau of Standards, diterbitkan ulang di situs web National Geodetic Survey dan Federal Register (Dok. 59-5442, Diarsipkan 30 Juni 1959, 8.45 pagi)
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Hofstad, Knut. "Mil". Store norske leksikon. Diakses tanggal 16 Juni 2022.