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Ronald J. Buta, « Galactic rings revisited - I. CVRHS classifications of 3962 ringed galaxies from the Galaxy Zoo 2 Database », Monthly Notices of the Royal Astronomical Society, vol. 471#4, , p. 4027-4046 (DOI10.1093/mnras/stx1829, Bibcode2017MNRAS.471.4027B, lire en ligne)
Ronald J. Buta, « Galactic rings revisited - I. CVRHS classifications of 3962 ringed galaxies from the Galaxy Zoo 2 Database », Monthly Notices of the Royal Astronomical Society, vol. 471#4, , p. 4027-4046 (DOI10.1093/mnras/stx1829, Bibcode2017MNRAS.471.4027B, lire en ligne)
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