Akashi-Ronquest N. The impact of biological preferences on parental investments in children and step-children. Rev Econ Househ. 2009 Mar 1;7(1):59-81.
Van Houtven CH, Wilson MR, Clipp EC. Informal care intensity and caregiver drug utilization. Rev Econ Househ. 2005;3(4):415-33.
Fleming AD, Xia X, McDicken WN, Sutherland GR, Fenn L. Myocardial velocity gradients detected by Doppler imaging. Br J Radiol. 1994 Jul 1;67(799):679-88. doi: 10.1259/0007-1285-67-799-679