Wilson, O. C. (1976-05), “Absolute magnitudes of stars from widths of chromospheric Ca II emission lines”, Astrophysical Journal205: 823-840, Bibcode: 1976ApJ...205..823W, doi:10.1086/154338
Hünsch, M.; Schmitt, J. H.M.M.; Voges, W. (1998-01), “The ROSAT all-sky survey catalogue of optically bright late-type giants and supergiants”, Astronomy & Astrophysics Supplement Series132: 155-171, Bibcode: 1998A&AS..132..155H, doi:10.1051/aas:1998287
Choi, Hyung-Jin; et al. (1995-08), “A Study of Variability in a Sample of G and K Giants”, Publications of the Astronomical Society of the Pacific107: 744-750, Bibcode: 1995PASP..107..744C, doi:10.1086/133617
Wilson, O. C. (1976-05), “Absolute magnitudes of stars from widths of chromospheric Ca II emission lines”, Astrophysical Journal205: 823-840, Bibcode: 1976ApJ...205..823W, doi:10.1086/154338
Gondoin, P.; Mangeney, A.; Praderie, F. (1987-03), “Solar-type giants : new X-ray detections from EXOSAT observations”, Astronomy & Astrophysics174: 187-196, Bibcode: 1987A&A...174..187G
Hünsch, M.; Schmitt, J. H.M.M.; Voges, W. (1998-01), “The ROSAT all-sky survey catalogue of optically bright late-type giants and supergiants”, Astronomy & Astrophysics Supplement Series132: 155-171, Bibcode: 1998A&AS..132..155H, doi:10.1051/aas:1998287
Choi, Hyung-Jin; et al. (1995-08), “A Study of Variability in a Sample of G and K Giants”, Publications of the Astronomical Society of the Pacific107: 744-750, Bibcode: 1995PASP..107..744C, doi:10.1086/133617