Gray, R. O.; Corbally, C. J. (2002). “A Spectroscopic Search for λ Bootis and Other Peculiar A-Type Stars in Intermediate-Age Open Clusters”. The Astronomical Journal (American Astronomical Society) 124 (2): 989–1000. doi:10.1086/341609. ISSN0004-6256.
Gray, R. O.; Corbally, C. J. (2002). “A Spectroscopic Search for λ Bootis and Other Peculiar A-Type Stars in Intermediate-Age Open Clusters”. The Astronomical Journal (American Astronomical Society) 124 (2): 989–1000. doi:10.1086/341609. ISSN0004-6256.