Tài liệu tham khảo WikiPedia: NGC_152 http://cseligman.com/text/atlas/ngc1a.htm#152 http://nedwww.ipac.caltech.edu/ http://simbad.u-strasbg.fr/simbad/sim-id?Ident=NGC... http://www.wikisky.org/?ra=0.54788888888889&de=-73...