Riedel، A. R.؛ Guinan, E. F.؛ DeWarf, L. E.؛ Engle, S. G.؛ McCook, G. P. (مايو 2005). "Barnard's Star as a Proxy for Old Disk dM Stars: Magnetic Activity, Light Variations, XUV Irradiances, and Planetary Habitable Zones". Bulletin of the American Astronomical Society. ج. 37: 442. Bibcode:2005AAS...206.0904R.