1. American Pet Products Association (APPA). (2011). APPA national pet ownership survey 2011–2012.
http://www.americanpetproducts.org/press_industrytrends.org
.
2. American Veterinary Medical Association (AVMA). (2012). U. S. pet ownership and demographic sourcebook. Schaumburg, IL: AVMA.
3. Ascione, F. R. (1992). Enhancing children’s attitudes about humane treatment of animals: Generalization to human-directed empathy. Anthrozoös, 5, 176–191.
4. Bodsworth, W., & Coleman, G. J. (2001). Children’s companion animal attachment bonds in single and two parent families. Anthrozoös, 14, 216–223.
5. Bronfenbrenner, U. (1979). The ecology of human development. Cambridge, MA: Harvard University Press.