Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
Allen, M. S.; Cowley, C. R. (1974). "Resolution of the praseodymium abundance anomaly in the Ba II stars". The Astrophysical Journal. 190: 601. Bibcode:1974ApJ...190..601A. doi:10.1086/152917.
Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. SIMBAD. Bibcode:1986EgUBV........0M.
Srivastava, R. K. (July 1988). "Eclipsing Binary Signatures in zeta Capricorni". Information Bulletin on Variable Stars. 3217: 1. Bibcode:1988IBVS.3217....1S.
Allen, M. S.; Cowley, C. R. (1974). "Resolution of the praseodymium abundance anomaly in the Ba II stars". The Astrophysical Journal. 190: 601. Bibcode:1974ApJ...190..601A. doi:10.1086/152917.