Harlan, E. A.; Taylor, D. C. (March 1970), "MK classification for F- and G-type stars. II", Astronomical Journal, 75 (2): 165–166, Bibcode:1970AJ.....75..165H, doi:10.1086/110956
Harlan, E. A.; Taylor, D. C. (March 1970), "MK classification for F- and G-type stars. II", Astronomical Journal, 75 (2): 165–166, Bibcode:1970AJ.....75..165H, doi:10.1086/110956