Ballard S, Christiansen JL, Charbonneau D, Deming D, Holman MJ, A'Hearn MF, Wellnitz DD, Barry RK, Kuchner MJ, Livengood TA, et al. A Search for Additional Planets in Five of the Exoplanetary Systems Studied by the NASA EPOXI Mission. \apj. 2011;732 (1) :41.