STANGHELLINI, Letizia; SHAW, Richard A.; VILLAVER, Eva. The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale. S. 194–202. Astrophysical Journal [online]. 2008-12-10 [cit. 2016-04-07]. Roč. 689, čís. 1, s. 194–202. Dostupné online. arXiv0807.1129. DOI10.1086/592395. Bibcode2008ApJ...689..194S. (anglicky)
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MOBBERLEY, Martin. The Caldwell Objects and How to Observe Them. [s.l.]: Springer Science+Business Media, LLC, 2009. Dostupné online. S. 128. (anglicky)
doi.org
dx.doi.org
STANGHELLINI, Letizia; SHAW, Richard A.; VILLAVER, Eva. The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale. S. 194–202. Astrophysical Journal [online]. 2008-12-10 [cit. 2016-04-07]. Roč. 689, čís. 1, s. 194–202. Dostupné online. arXiv0807.1129. DOI10.1086/592395. Bibcode2008ApJ...689..194S. (anglicky)
harvard.edu
adsabs.harvard.edu
STANGHELLINI, Letizia; SHAW, Richard A.; VILLAVER, Eva. The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale. S. 194–202. Astrophysical Journal [online]. 2008-12-10 [cit. 2016-04-07]. Roč. 689, čís. 1, s. 194–202. Dostupné online. arXiv0807.1129. DOI10.1086/592395. Bibcode2008ApJ...689..194S. (anglicky)