Döllinger, M. P., Hatzes, A. P., Pasquini, L., Guenther, E. W., Hartmann, M., Girardi, L., et al. (2007). Discovery of a planet around the K giant star 4 Ursae Majoris. Astronomy & Astrophysics, 472(2), 649-652. doi:10.1051/0004-6361:20066987.