for Earth-like planets in the habitable zone: I – Very low-mass planets around HD20794, HD85512 and HD192310. 2011. arXiv:1108.3447 . 引文格式1维护:显式使用等标签 (link)
1086/523942. 引文使用过时参数coauthors (帮助) Shiga, David. Sun's 'twin' an ideal hunting ground for alien life. New Scientist. 2007-10-03 [2009-05-28]. (原始内容存档于2012-03-03)