Morrison, J. E.; et al. (2001-03), “The Guide Star Catalog, Version 1.2: An Astrometric Recalibration and Other Refinements”, Astronomical Journal121 (3): 1752-1763, Bibcode: 2001AJ....121.1752M, doi:10.1086/319383
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Morrison, J. E.; et al. (2001-03), “The Guide Star Catalog, Version 1.2: An Astrometric Recalibration and Other Refinements”, Astronomical Journal121 (3): 1752-1763, Bibcode: 2001AJ....121.1752M, doi:10.1086/319383