1. Environmental enrichment: an historical perspective;Young,2003
2. Brambell report,1965
3. Farm Animal Welfare Council press release December 1979. Accessed October 2013 at www.fawc.org.uk/pdf/fivefreedoms1979/pdf.
4. AAFP and ASFM Feline Environmental Needs Guidelines;Ellis;J Fel Med Surg,2013
5. A game of cat and house: spatial patterns and behaviour of 14 domestic cats (Felis catus) in the home;Bernstein;Anthrozoos,1996