Boyles, J.; Lorimer, D. R.; Turk, P. J.; Mnatsakanov, R.; Lynch, R. S.; Ransom, S. M.; Freire, P. C.; Belczynski, K. (November 2011), ”Young Radio Pulsars in Galactic Globular Clusters”, The Astrophysical Journal 742 (1): 51, doi:10.1088/0004-637X/742/1/51, Bibcode: 2011ApJ...742...51B.
Testa, Vincenzo; Corsi, Carlo E.; Andreuzzi, Gloria; Iannicola, Giacinto; Marconi, Gianni; Piersimoni, Anna Marina; Buonanno, Roberto (February 2001), ”Horizontal-Branch Morphology and Dense Environments: Hubble Space Telescope Observations of Globular Clusters NGC 2298, 5897, 6535, and 6626”, The Astronomical Journal 121 (2): 916–934, doi:10.1086/318752, Bibcode: 2001AJ....121..916T
Bogdanov, Slavko; van den Berg, Maureen; Servillat, Mathieu; Heinke, Craig O.; Grindlay, Jonathan E.; Stairs, Ingrid H.; Ransom, Scott M.; Freire, Paulo C. C.; et al. (April 2011), ”Chandra X-ray Observations of 12 Millisecond Pulsars in the Globular Cluster M28”, The Astrophysical Journal 730 (2): 81, doi:10.1088/0004-637X/730/2/81, Bibcode: 2011ApJ...730...81B
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Boyles, J.; Lorimer, D. R.; Turk, P. J.; Mnatsakanov, R.; Lynch, R. S.; Ransom, S. M.; Freire, P. C.; Belczynski, K. (November 2011), ”Young Radio Pulsars in Galactic Globular Clusters”, The Astrophysical Journal 742 (1): 51, doi:10.1088/0004-637X/742/1/51, Bibcode: 2011ApJ...742...51B.
Shapley, Harlow; Sawyer, Helen B. (August 1927), ”A Classification of Globular Clusters”, Harvard College Observatory Bulletin 849 (849): 11–14, Bibcode: 1927BHarO.849...11S.
Bogdanov, Slavko; van den Berg, Maureen; Servillat, Mathieu; Heinke, Craig O.; Grindlay, Jonathan E.; Stairs, Ingrid H.; Ransom, Scott M.; Freire, Paulo C. C.; et al. (April 2011), ”Chandra X-ray Observations of 12 Millisecond Pulsars in the Globular Cluster M28”, The Astrophysical Journal 730 (2): 81, doi:10.1088/0004-637X/730/2/81, Bibcode: 2011ApJ...730...81B
