See Table 1, Doyle, J. G.; Butler, C. J. (1990). "Optical and infrared photometry of dwarf M and K stars". Astronomy and Astrophysics. 235: 335–339. Bibcode:1990A&A...235..335D. and p. 57, Peebles, P. J. E. (1993). Principles of Physical Cosmology. Princeton, New Jersey: Princeton University Press. ISBN0691019339.
See Table 1, Doyle, J. G.; Butler, C. J. (1990). "Optical and infrared photometry of dwarf M and K stars". Astronomy and Astrophysics. 235: 335–339. Bibcode:1990A&A...235..335D. and p. 57, Peebles, P. J. E. (1993). Principles of Physical Cosmology. Princeton, New Jersey: Princeton University Press. ISBN0691019339.