Sandage, Allan. 1953. The color-magnitude diagram for the globular cluster M3. The Astronomical Journal (engleski). 58: 61–75. Bibcode:1953AJ.....58...61S. doi:10.1086/106822
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Sandage, Allan. 1953. The color-magnitude diagram for the globular cluster M3. The Astronomical Journal (engleski). 58: 61–75. Bibcode:1953AJ.....58...61S. doi:10.1086/106822