J. A. Bearden (1965): "Selection of the W Kα₁ as the X-Ray Wavelength Standard". Physical Review 2nd series, volume 137, issue 2B, pages 455B–B461. doi:10.1103/PhysRev.137.B455
Albert A. Michelson (1895): "Détermination expérimentale de la valeur du mètre en longueurs d'ondes lumineuses" (= "Experimental determination of the value of the meter in terms of the lengths of light waves"); translated to French by Jean-René Benoît. Travaux et Mémoires du Bureau International des Poids et Mesures, volume 11, pages 1–85. Quote from p. 85, back-translated: "... the final conclusion of this work is that the fundamental unit of the metric system is represented by the following numbers of wavelengths of three emissions of cadmium, in air at 15°C and at a pressure of 760mm: Red emission … 1m = 1553163,5λR ... It follows that the wavelengths of these emissions, always at 15°C and at 760mm, are (averages of three determinations): λR = 0,64384722μ" (where [1μ = 1×10−6m]"
International Astronomical Union (2012): "Resolution B2: On the re-definition of the astronomical unit of length". Proceedings of the XXVIII General Assembly of International Astronomical Union, Beijing, China. Quote: "... recommends ... 5. that the unique symbol 'au' be used for the astronomical unit."
Ambler Thompson and Barry N. Taylor (2009): "B.8 Factors for Units Listed Alphabetically". NIST Guide to the SI, National Institutes of Standards and Technology. Accessed on 2019-03-02
Oxford University Press (2019) Entry "angstrom" by Oxford Living Dictionaries online; Archived on 2019-03-06. Spellings "angstrom" [aŋstrəm] and "ångström"; symbol "Å"
Oxford University Press (1986) Entry "Ångström (unit)" in the Oxford English Dictionary, 2nd edition (1986); Archived on 2021-11-22. Spellings "Ångström" [ɔːŋstrœm] (capitalized) and "angstrom" (lowercase); symbols "Å", "Å.U.", "A.U." Quote: "The International Ångström (I.Å.) was defined in 1907 in terms of the wavelength of cadmium which in standard conditions is 6438·4696 I.Å. When the metre was defined in terms of the wavelength of krypton in 1960 the Ångström became exactly equal to 10−8 cm."
Oxford Journals (2012): "Instructions for Authors". Monthly Notices of the Royal Astronomical Society. Archived on 22 October 2012 Quote: "The units of length/distance are Å, nm, μm, mm, cm, m, km, au, light-year, pc."
American Astronomical Society (2016): "Manuscript Preparation: AJ & ApJ Author Instructions". Archived on 2016-02-21. Quote: "Use standard abbreviations for ... natural units (e.g., au, pc, cm)."
