Getman, K. V.; Feigelson, E. D.; Kuhn, M. A. (2014). "Core-Halo Age Gradients and Star Formation in the Orion Nebula and NGC 2024 Young Stellar Clusters". Astrophysical Journal. Quyển 787 số 2. tr. 109. arXiv:1403.2742. Bibcode:2014ApJ...787..109G. doi:10.1088/0004-637X/787/2/109.
Getman, K. V.; Feigelson, E. D.; Kuhn, M. A. (2014). "Core-Halo Age Gradients and Star Formation in the Orion Nebula and NGC 2024 Young Stellar Clusters". Astrophysical Journal. Quyển 787 số 2. tr. 109. arXiv:1403.2742. Bibcode:2014ApJ...787..109G. doi:10.1088/0004-637X/787/2/109.
Getman, K. V.; Feigelson, E. D.; Kuhn, M. A. (2014). "Core-Halo Age Gradients and Star Formation in the Orion Nebula and NGC 2024 Young Stellar Clusters". Astrophysical Journal. Quyển 787 số 2. tr. 109. arXiv:1403.2742. Bibcode:2014ApJ...787..109G. doi:10.1088/0004-637X/787/2/109.