parsec \symbunite{pc}
1964 / The System of Astronomical Constants. Part I / G. A. Wilkins / Quarterly Journal of the Royal Astronomical Society 5 (1964) p. 23 [lien]
1965 / The System of Astronomical Constants. Part II / G. A. Wilkins / Quarterly Journal of the Royal Astronomical Society 6 (1965) p. 70 [lien]