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.
Lawson DH, Jick H, Rothman KJ. Coffee and tea consumption and breast disease. Surgery. 1981 Jan 1;90(5):801-3.