Tài liệu tham khảo WikiPedia: NGC_7027 http://www.astronomy.com/asy/default.aspx?c=a&id=3... http://nedwww.ipac.caltech.edu http://spider.ipac.caltech.edu/staff/latter/N7027d... http://www.noao.edu/outreach/aop/observers/n7027.h... //arxiv.org/abs/astro-ph/0102468 //doi.org/10.1038%2Fs41586-019-1090-x //doi.org/10.1051%2F0004-6361:20000435 //doi.org/10.1086%2F167011 //doi.org/10.1086%2F319651 //doi.org/10.1093%2Fmnras%2F290.4.l71
