Stanghellini, Letizia; Shaw, Richard A.; Villaver, Eva (2008). "The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale". The Astrophysical Journal. 689 (1): 194–202. arXiv:0807.1129. doi:10.1086/592395. ISSN0004-637X.
Palen, Stacy; Balick, Bruce; Hajian, Arsen R.; Terzian, Yervant; Bond, Howard E.; Panagia, Nino (2002). "Hubble Space Telescope Expansion Parallaxes of the Planetary Nebulae NGC 6578, NGC 6884, NGC 6891, and IC 2448". The Astronomical Journal. 123 (5): 2666–2675. arXiv:astro-ph/0202003. doi:10.1086/339838. ISSN0004-6256.
Stanghellini, Letizia; Shaw, Richard A.; Villaver, Eva (2008). "The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale". The Astrophysical Journal. 689 (1): 194–202. arXiv:0807.1129. doi:10.1086/592395. ISSN0004-637X.
Palen, Stacy; Balick, Bruce; Hajian, Arsen R.; Terzian, Yervant; Bond, Howard E.; Panagia, Nino (2002). "Hubble Space Telescope Expansion Parallaxes of the Planetary Nebulae NGC 6578, NGC 6884, NGC 6891, and IC 2448". The Astronomical Journal. 123 (5): 2666–2675. arXiv:astro-ph/0202003. doi:10.1086/339838. ISSN0004-6256.
Stanghellini, Letizia; Shaw, Richard A.; Villaver, Eva (2008). "The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale". The Astrophysical Journal. 689 (1): 194–202. arXiv:0807.1129. doi:10.1086/592395. ISSN0004-637X.
Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. ISSN0004-6361.
Palen, Stacy; Balick, Bruce; Hajian, Arsen R.; Terzian, Yervant; Bond, Howard E.; Panagia, Nino (2002). "Hubble Space Telescope Expansion Parallaxes of the Planetary Nebulae NGC 6578, NGC 6884, NGC 6891, and IC 2448". The Astronomical Journal. 123 (5): 2666–2675. arXiv:astro-ph/0202003. doi:10.1086/339838. ISSN0004-6256.