Não informado. (1903). Circular of the Bureau of Standards. U.S. Department of Commerce, National Bureau of Standards.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Circular of the Bureau of Standards. Washington: U.S. Department of Commerce, National Bureau of Standards, 1903.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Circular of the Bureau of Standards. U.S. Department of Commerce, National Bureau of Standards, 1903.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.