Tài liệu tham khảo WikiPedia: Sao lùn http://orbi.ulg.ac.be/jspui/handle/2268/6224 http://adsabs.harvard.edu/abs/2009A&A...506.1055N //arxiv.org/abs/0908.1461 //dx.doi.org/10.1051%2F0004-6361%2F200912659