@article {2011ApJ...726...73H,
	title = {The NASA-UC Eta-Earth Program. II. A Planet Orbiting HD 156668 with a Minimum Mass of Four Earth Masses},
	journal = {\apj},
	volume = {726},
	number = {2},
	year = {2011},
	month = {jan},
	pages = {73},
	keywords = {Astrophysics - Earth and Planetary Astrophysics, Planetary systems, stars: individual: HD 156668, techniques: radial velocities},
	doi = {10.1088/0004-637X/726/2/73},
	author = {Howard, Andrew W. and Johnson, John Asher and Marcy, Geoffrey W. and Fischer, Debra A. and Wright, Jason T. and Henry, Gregory W. and Isaacson, Howard and Valenti, Jeff A. and Anderson, Jay and Piskunov, Nikolai E.}
}
