Tài liệu tham khảo WikiPedia: NGC_891 http://cseligman.com/text/atlas/ngc8a.htm#891 http://www.dsi-astronomie.de/NGC891.htm http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsear... http://cbat.eps.harvard.edu/lists/Supernovae.html#... http://antwrp.gsfc.nasa.gov/apod/ap990919.html //arxiv.org/abs/astro-ph/0011223 //arxiv.org/abs/astro-ph/9704107 //doi.org/10.1086%2F313041 //doi.org/10.1086%2F318301 //doi.org/10.1086%2F382905
