a “Animals have complex dreams, MIT researcher proves. Study may advance understanding of human learning and memory,” Massachusetts Institute of Technology, News Office, January 24, 2001.
b “Do animals dream?,” Posted by EarthSky in EARTH, February 7, 2019.
c American Psychiatric Association, (2013) Diagnostic and Statistical Manual of Mental Disorders (5th ed.), 2013; Washington, DC
d Peterson, T. (2016, February 4). Understanding PTSD Nightmares and Flashbacks, HealthyPlace. Retrieved on 2020, May 9 from https://www.healthyplace.com/ptsd-and-stress-disorders/ptsd/understanding-ptsd-nightmares-and-flashbacks.
e America Veterinary Medical Association, JAVMA news; “Pet ownership spending going strong; published on May 08, 2019.
f Federation of European Companion Animal Veterinary Associations, “Which country spends the most on its pets?”; posted 22/02/2020;
https://www.fecava.org.
g Stephen Robert Kellert and Alan R. Felthous, “Childhood Cruelty toward Animals among Criminals and Noncriminals,” in Human Relations 38(12):1113-1129 · December 1985.