a Kevin Wagner et al. “Direct Imaging Discovery of a Jovian Exoplanet within a Triple-Star System,” Science, Vol. 353, 12 August 2016. p. 673.
u . . “...a number of other substellar objects have been observed in triple-star systems.” Rebecca Oppenheimer, “Making Sense of the Exoplanet Zoo,” Science, Vol. 353, 12 August 2016. p. 644.
b . David Fleischer, “The Galaxy Maker,” Science Digest, Vol. 89, October 1981, pp. 12, 116.