Tài liệu tham khảo WikiPedia: Thiên_hà_Ngọc_Phu http://www.jpl.nasa.gov/news/news.php?release=2013... //arxiv.org/abs/astro-ph/0302045 //arxiv.org/abs/astro-ph/0410065 //doi.org/10.1051%2F0004-6361:20030170 //doi.org/10.1086%2F382905 //doi.org/10.1086%2F426368 http://hubblesite.org/newscenter/newsdesk/archive/... http://hubblesite.org/newscenter/newsdesk/archive/... http://server1.wikisky.org/starview?object=Thi%C3%... http://www.wikisky.org/?object=Thi%C3%AAn+h%C3%A0+...
