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.
Milunsky A, Morris JS, Jick H, Rothman KJ, Ulcickas M, Jick SS, Shoukimas P, Willett W. Maternal zinc and fetal neural tube defects. Teratology. 1992 Oct 1;46(4):341-8.
Rothman KJ, Fyler DC. Association of congenital heart defects with season and population density. Teratology. 1976 Feb;13(1):29-34.