NASA Exoplanet Science Institute. Retrieved 4 June 2016. ↑ http://www.skyandtelescope.com/astronomy-news/welcome-lhs-1140b-super-earth-habitable-zone/ ↑ Evidence for at least three planet candidates orbiting HD20794 (PDF), May 16, 2017, pp. 1, 9, retrieved May 19, 2017 ↑ "HADES RV Programme with HARPS-N at TNG: V. A super-Earth on the inner edge of the habitable zone oft he nearby M-dwarf GJ 625".