Koupelis, Theo; Karl F. Kuhn (2007). In Quest of the Universe 5th ed. [S.l.]: Jones & Bartlett Publishers. p. 149. ISBN0-7637-4387-9. Consultado em 2 de abril de 2008
harvard.edu
ui.adsabs.harvard.edu
Braes, L.L.E. (1974). «Radio Continuum Observations of Stellar Sources». IAU Symposium No.60, Maroochydore, Australia, September 3–7, 1973. 60: 377–381. Bibcode:1974IAUS...60..377B