R. Lynds, A. Toomre (1976). “On the interpretation of ring galaxies : the binary ring system II Hz4”. Astrophysical Journal209: 328-388. Bibcode: 1976ApJ...209..382L. doi:10.1086/154730.
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R. Lynds, A. Toomre (1976). “On the interpretation of ring galaxies : the binary ring system II Hz4”. Astrophysical Journal209: 328-388. Bibcode: 1976ApJ...209..382L. doi:10.1086/154730.