Zhang & Liu, 2006 Zhang, Y.; Liu, X.-W. (2006), Ian F. Corbett. (ed.), The Fe/Ni ratio in the Ant Nebula Mz 3, Proceedings of the International Astronomical Union, Planetary Nebulae in our Galaxy and Beyond, Proceedings of the International Astronomical Union, Symposium #234, 2 (S234), Cambridge, MA: Cambridge University Press: 547–548, arXiv:astro-ph/0605180, Bibcode:2006IAUS..234..547Z, doi:10.1017/S1743921306004170
Zhang & Liu, 2006 Zhang, Y.; Liu, X.-W. (2006), Ian F. Corbett. (ed.), The Fe/Ni ratio in the Ant Nebula Mz 3, Proceedings of the International Astronomical Union, Planetary Nebulae in our Galaxy and Beyond, Proceedings of the International Astronomical Union, Symposium #234, 2 (S234), Cambridge, MA: Cambridge University Press: 547–548, arXiv:astro-ph/0605180, Bibcode:2006IAUS..234..547Z, doi:10.1017/S1743921306004170
Zhang & Liu, 2006 Zhang, Y.; Liu, X.-W. (2006), Ian F. Corbett. (ed.), The Fe/Ni ratio in the Ant Nebula Mz 3, Proceedings of the International Astronomical Union, Planetary Nebulae in our Galaxy and Beyond, Proceedings of the International Astronomical Union, Symposium #234, 2 (S234), Cambridge, MA: Cambridge University Press: 547–548, arXiv:astro-ph/0605180, Bibcode:2006IAUS..234..547Z, doi:10.1017/S1743921306004170