References: A.R. McConnell, C.M. Brown, T.M. Shoda, L.E. Stayton, and C.E. Martin. "Friends with Benefits: On the Positive Consequences of Pet Ownership." Journal of Personality and Social Psychology. Vol. 101. 2011 "Time to Eat the Dog? The Real Guide to Sustainable Living." By Brenda and Robert Vale. London. Thames and Hudson.