1. GfK. Global GfK survey: pet ownership Germany: GfK; 2016 [16/11/2017]. http://www.gfk.com/fileadmin/user_upload/website_content/Global_Study/Documents/Global-GfK-survey_Pet-Ownership_2016.pdf.
2. Companion Animal Adoption Study;L Neidhart;Journal of Applied Animal Welfare Science,2002
3. Obtaining a Pet: Realistic Expectations;A Marder;Veterinary Clinics of North America—Small Animal Practice,2008
4. American Society for the Prevention of Cruelty to Animals (ASPCA). Shelter Intake and Surrender: Pet Statistics USA2017 [12/12/2017]. http://www.aspca.org/animal-homelessness/shelter-intake-and-surrender/pet-statistics.
5. Surrendered and stray dogs in Australia—Estimation of numbers entering municipal pounds, shelters and rescue groups and their outcomes;D Chua;Animals,2017