Citation:
Gautier, T. N. III, Charbonneau D, Rowe JF, Marcy GW, Isaacson H, Torres G, Fressin F, Rogers LA, Désert J-M, Buchhave LA, et al. Kepler-20: A Sun-like Star with Three Sub-Neptune Exoplanets and Two Earth-size Candidates. \apj. 2012;749 (1) :15.