Hartman J D, Bakos GÁ, Sato B, Torres G, Noyes R W, Latham D W, Kovács G, Fischer D A, Howard A W, Johnson J A, et al. HAT-P-18b and HAT-P-19b: Two Low-density Saturn-mass Planets Transiting Metal-rich K Stars. \apj. 2011;726 (1) :52.