Wang, Harry H.X., Wang, Jia Ji, Lawson, Kenny D., Wong, Samuel Y.S., Wong, Martin C.S., Li, Fang Jian, Wang, Pei Xi, Zhou, Zhi Heng, Zhu, Chun Yan, Yeong, Jason Yao Q., Griffiths, Sian M., and Mercer, Stewart W. (2015) Relationships of multimorbidity and income with hospital admissions in 3 health care systems. Annals of Family Medicine, 13 (2). pp. 164-167.