1. World Health Organizationhttp://www.who.int/maternal_child_adolescent/topics/child/en/
2. Developing through Relationships: Origins of Communication, Self, and Culture;Fogel,1993
3. Attachment and Loss;Bowlby,1969
4. Pet Industry Market Size & Ownership Statisticshttp://www.americanpetproducts.org/press_industrytrends.asp
5. Statisticshttp://www.pfma.org.uk/statistics/